Volume 43,2024 Issue 2

Infrared Materials and Devices

• Study on the multifunctional sequential structure film of perspective/shading/temperature control/infrared stealth

  WANG Long, WANG Liu-Ying, LIU Gu, GE Chao-Qun, WANG Bin, XU Ke-Jun, WANG Wen-Hao, HU Ling-Jie

  2024,43(2):143-149, DOI: 10.11972/j.issn.1001-9014.2024.02.001

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  To solve the spectral demand and material design conflicts of multifunctional coupling and integration of optical materials， a collaborative design method based on ［TiAlN/Ag］²/TiAlN sequential structure film for visible transmission induction and infrared radiation suppression is proposed， interpreting the new principles and mechanisms of multifunctional coupling of sequential structure film materials. Meanwhile， its optical compatibility performance is characterized. It shows that the ［TiAlN （thickness 30 nm）/Ag （thickness 15 nm）］ ²/TiAlN （thickness 30 nm） sequential composite film has the optical characteristics of band-pass selective transmission and mid-far infrared low radiation， which can better realize the multifunctional compatibility effects of perspective， shading， low radiation temperature control， and infrared stealth， and can be used in the radiation temperature control and infrared stealth application fields of special glasses such as military vehicles and green buildings.

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• Study on the optical properties of VO₂ thin films under varied temperatures and the protection performance against 1550 nm laser

  DUAN Jia-Xin, JIANG Lin, ZHENG Guo-Bin, DING Chang-Chun, HUANG Jing-Guo, LIU Yi, GAO Yan-Qing, ZHOU Wei, HUANG Zhi-Ming

  2024,43(2):150-157, DOI: 10.11972/j.issn.1001-9014.2024.02.002

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  Vanadium dioxide materials， which show semiconductor-metal phase transition， can be used for protection of photoelectric detectors against laser blinding weapons. The structure， morphology and optical properties of vanadium dioxide thin films prepared by radio frequency magnetron sputtering at different temperatures were reported. The visible to infrared ellipsometric parameters of vanadium dioxide film at 20-100 were measured by an ellipsometer. The optical properties of vanadium dioxide films before the phase transition were obtained by Gaussian and Lorentz model， and the optical properties after the phase transition were obtained by adding a Drude model. The refractive index and extinction coefficient at varied temperatures between 300 nm and 1 700 nm were obtained. The transmittance spectra of 1 550 nm infrared laser at varied power densities show that the threshold power of phase transformation for the VO₂ film is about 12 W/cm²， where the transmittance decreases sharply from 51% to 15%-17%， and the switching rate is about 69%.

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• Study on the relationship between polarization and transverse modes of narrow ridge waveguide semiconductor lasers

  SONG Liang, HE Yu-Wen, WANG Hao-Miao, ZHOU Kun, DU Wei-Chuan, LI Yi, HE Lin-An, HU Yao, ZHANG Liang, GAO Ping-Kuan, WANG Xin-Yang, GAO Song-Xin, TANG Chun

  2024,43(2):158-165, DOI: 10.11972/j.issn.1001-9014.2024.02.003

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  A numerical calculation model of the narrow ridge waveguide was established based on the effective refractive index method. The relationship between the polarization characteristics and the transverse mode of the InGaAs quantum well narrow ridge waveguide semiconductor laser was studied experimentally. According to theoretical calculations， the effective refractive index difference of the TM-like mode in the ridge waveguide is larger in the direction of the slow axis. The confinement factors of the TM-like mode are larger than those of the TE-like mode， and the slow-axis high-order mode is more likely to appear. As the height of the ridge waveguide increases， the fast-axis high-order modes are truncated， and the confinement factor of the TE₀₀-like mode gradually increases to be similar to that of the TM₀₀-like mode. The slow-axis high-order mode is suppressed due to its large scattering loss， theoretically achieving high polarization， and near diffraction limit beam-quality laser output. In terms of experiments， a narrow ridge waveguide semiconductor laser with a high polarization extinction ratio and a fundamental transverse mode was fabricated by the gain polarization characteristics of quantum well materials and by designing the height and width of the ridge.

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• Uncooled InAsSb-based high-speed mid-wave infrared barrier detector

  JIA Chun-Yang, DENG Gong-Rong, ZHAO Peng, ZHU Zhi-Zhen, ZHAO Jun, ZHANG Yi-Yun

  2024,43(2):166-172, DOI: 10.11972/j.issn.1001-9014.2024.02.004

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  The demand for high-speed response mid-wave infrared （MWIR） photodetectors （PDs） is gradually increasing in emerging fields such as free-space optical communication and frequency comb spectroscopy. The XB_nn barrier infrared photodetectors greatly suppress shot noise originated from the device dark current. In this work， InAsSb/AlAsSb/AlSb-based nBn and pBn barrier MWIR PDs were grown on GaSb substrates using molecular beam epitaxy （MBE）. The GSG PDs were fabricated to realize the radio frequency （RF） response testing. X-ray diffraction （XRD） and atomic force microscopy （AFM） results indicate that both epitaxial structures exhibit good crystal quality. The 90 μm diameter pBn PDs exhibit a lower dark current density of 0.145 A/cm2 compared to the nBn PDs operating at room temperature （RT） and a reverse bias of 400 mV， which indicates the uncooled barrier PDs perform with low noise. Capacitance tests reveal that the pBn PDs， operating at zero bias， show a fully depleted barrier layer and partially depleted absorption region， while the nBn absorption region also exhibits partial depletion. RF response characterization demonstrates that the 90 μm diameter pBn PDs achieve 3 dB bandwidth of 2.62 GHz at room temperature and under a 3 V reverse bias， which represents a 29.7% improvement over the corresponding nBn PDs， only achieving 3 dB bandwidth of 2.02 GHz. This signifies a preliminary achievement of uncooled barrier MWIR PDs capable of fast detection.

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• Study on crystal quality of materials in Zone I of APD P-I-N HgCdTe

  SHEN Chuan, ZHANG Jing, YANG Liao, GUO Hui-Jun, XIE Hao, ZHOU Mei-Hua, CHEN Lu, HE Li

  2024,43(2):173-177, DOI: 10.11972/j.issn.1001-9014.2024.02.005

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  In this paper， we investigated the crystal quality of Mercury Cadmium Telluride （HgCdTe） materials in the key avalanche region of avalanche photodiode detectors （APDs） with MWIR PIN structure. We simulated the entire process of the PIN APD device on the experimental materials and used differential Hall testing and differential minority lifetime testing to evaluate the material’s real crystal quality in the key avalanche area. It is found that the crystal quality of the avalanche region under the optimized process is good. Its Shockley-Read-Hall （SRH） lifetime is 20.7 μs， which can be comparable to that of the primary HgCdTe materials. This meets the development requirements for high-quality MWIR HgCdTe avalanche devices. Additionally， based on the obtained SRH lifetime in the avalanche region， we conducted corresponding two-dimensional numerical simulations on HgCdTe APD structural devices to determine the theoretically optimal dark current density of 8.7×10^-10 A/cm².

• High-performance spectro-polarimetric filter by integrating subwavelength gratings with Fabry-Perot filter

  ZHU Yuan-Yu, GUAN Xue-Yu, YU Pei-Qi, LIU Qing-Quan, JIA Qi-Xiang, WU Jie, LI Chen-Lu, LI Zhi-Feng, WANG Shao-Wei

  2024,43(2):178-185, DOI: 10.11972/j.issn.1001-9014.2024.02.006

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  Abstract:

  Spectral polarization imaging technology is a novel optical imaging technique that not only enhances the amount of information acquired from targets， but also reduces background noise， which can capture target details and detect disguised targets. This paper presents a spectro-polarimetric device by integrating subwavelength gratings with Fabry-Perot （F-P） filter， which can obtain ultra-high spectral resolution and polarization extinction ratio with high control flexibly on both spectrum and polarization. A spectro-polarimetric filter （SPF） has been designed to obtain 4 spectral channels of stokes parameters simultaneously. Simulation results show that it has a spectral resolution （SR， ） of 217 and a polarization extinction ratio （PER） of . The polarization extinction ratio of subwavelength grating is measured to be over 500 PER with 90% transmission efficiency. The spectral resolution of all-dielectric F-P filter is measured to be 30 with 60% transmission efficiency in the long wave infrared band. The designed method is universal and can be used in a wide range of wavelength bands such as visible， infrared， and even terahertz. It has great potential applications in fields such as micro-polarization spectrometers and full-stokes polarization detection， benefiting from these advantages.

Terahertz and Millimeter Wave Technology

• A 66-112.5 GHz low noise amplifier with minimum NF of 3.9 dB in 0.1-μm GaAs pHEMT technology

  LI Ze-Kun, CHEN Ji-Xin, ZHENG Si-Dou, HONG Wei

  2024,43(2):186-190, DOI: 10.11972/j.issn.1001-9014.2024.02.007

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  A wideband low noise amplifier （LNA） covering the whole W-band in 0.1-μm GaAs pHEMT technology is designed. To reduce the inter-stage crosstalk and obtain wideband matching， a bypass circuit composed of dual shunt capacitors is proposed to provide wideband RF grounding. The wideband input matching and optimal noise matching are implemented by a dual-resonance input matching network. The measurement results exhibit a peak gain of 20.4 dB at 108 GHz. The measured small signal gain is 16.9-20.4 dB across 66-112.5 GHz. The measured noise figure （NF） is 3.9 dB at 90 GHz. The measured input 1-dB compression point （IP_1dB） is around -12 dBm in W-band.

• A metamaterial absorber with electrically and thermally tunable absorption frequency and absorptivity

  HU Bao-Jing, HUANG Ming, ZHAO Jin-Yan, YANG Li, YANG Yu-Lin

  2024,43(2):191-198, DOI: 10.11972/j.issn.1001-9014.2024.02.008

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  A dual-tunable "perfect" metamaterial absorber composed of a "Tian-zi"-shaped bulk Dirac semimetal （BDS） resonator and strontium titanate （STO） is proposed in this work and systematically studied by performing numerical simulations. From the acquired results， it is demonstrated that the absorber can achieve 99% absorption rate at 2.613 1 THz when the BDS Fermi energy is 40 meV and the STO temperature is 400 K. Moreover， both dynamics dual-tuning of the absorption frequency and absorption rate of the absorber can be successfully achieved by varying the BDS Fermi energy level and the STO temperature. Additionally， the absorber''s performance is theoretically analyzed using both coupled mode theory （CMT） and equivalent circuit model （ECM）. Finally， the changes in the absorber''s absorption spectrum are further discussed when each parameter of the model is modified， providing thus a solid theoretical basis for the design of dual-tunable filters and absorbers.

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• High-performance MOCVD-SiN_x/AlN/GaN MIS-HEMTs with low noise and high linearity for millimeter waves

  YUAN Jing, JING Guan-Jun, WANG Jian-Chao, WANG Liu, GAO Run-Hua, ZHANG Yi-Chuan, YAO Yi-Xu, WEI Ke, LI Yan-Kui, CHEN Xiao-Juan

  2024,43(2):199-205, DOI: 10.11972/j.issn.1001-9014.2024.02.009

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  In this paper， we demonstrated SiN_x/AlN/GaN metal-insulator-semiconductor high electron mobility transistors （MIS-HEMTs） with low noise and high linearity， by in-situ growth of SiN_x gate dielectrics on ultra-thin barrier AlN/GaN heterostructure. Deep-level transient spectroscopy （DLTS） shows a traps-level depth of 0.236 eV， a capture cross-section of 3.06×10^-19 cm^-2， and an extracted interface state density of 10¹⁰-10¹² cm^-2eV^-1， which confirms that the grown SiN_x can reduce the interface state. The devices exhibit excellent DC， small signal， and power performance， with a maximum saturation output current （I_dmax） of 2.2 A/mm at the gate voltage （V_gs） of 2 V and the gate length of 0.15 μm， a maximum current cutoff frequency （f_T） of 65 GHz， a maximum power cutoff frequency （f_MAX） of 123 GHz， a minimum noise figure （NF_min） of the device of 1.07 dB and the gain of 9.93 dB at 40 GHz. The two-tone measurements at the V_ds of 6V， yield a third-order intermodulation output power （OIP3） of 32.6 dBm， and OIP3/P_dc of 11.2 dB. Benefited from the high-quality SiN_x/AlN interface， the MIS-HEMTs exhibited excellent low noise and high linearity， revealing its potential in applications of millimeter waves.

Infrared Spectroscopy and Spectral Analysis

• Terahertz spectroscopy and weak interaction analysis of cinnamic acid derivatives

  ZHENG Zhuan-Ping, ZHAO Shuai-Yu, LIU Yu-Hang, ZENG Fang

  2024,43(2):206-213, DOI: 10.11972/j.issn.1001-9014.2024.02.010

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  The absorption peaks of three cinnamic acid derivatives （CADs）： p-coumaric acid （PCA）， trans o-coumaric acid （OCA）， and 4-fluorocinnamic acid （4-FCA） were measured using terahertz time-domain spectroscopy （THz-TDS） in the range of 0.5-3.5 THz. To identify the origins of the THz absorption peaks in the three samples， the density functional theory （DFT） was employed along with the vibrational mode automatic relevance determination （VMARD） method. Additionally， the molecular force field energy decomposition analysis （EDA-FF） was used to analyze the forms of weak intermolecular forces in the molecular systems. Visualization analysis was conducted through the visualization of molecular dynamics （VMD） using atom coloring to study the contribution types and strengths of weak intermolecular forces by atoms in the molecular systems. This combination of THz-TDS， DFT， VMARD， and EDA-FF methods not only effectively distinguishes organic molecules with structural isomers or structural similarities but also provides valuable reference data for uncovering their biochemical functionalities.

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Remote Sensing Technology and Application

• A new method for retrieving the near-space temperature profile based on the 1.27 μm O₂ airglow

  WANG Dao-Qi, WANG Hou-Mao, HU Xiang-Rui, HE Wei-Wei, LI Fa-Quan, WU Kui-Jun

  2024,43(2):214-224, DOI: 10.11972/j.issn.1001-9014.2024.02.011

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  The high radiation intensity and weak self-absorption effect of the O₂（a¹?_g） airglow in the 1.27 μm band make it an ideal target source for retrieval of the atmospheric temperature in the near-space. Based on the theory of O₂ airglow spectral and the "onion-peeling" algorithm， the near-infrared limb-viewing data of the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY （SCIAMACHY） were successfully used to retrieve the atmospheric temperature profiles in the range of 50-100 km. Comparison with SABER， ACE-FTS and LIDAR observations shows that the temperature measurement error is better than ±10 K in the tangential altitude of 55-85 km. However， in the space region below 55 km and above 85 km， the temperature retrieval results show significant bias due to the influences of self-absorption effects， atmospheric scattering， and spectral contamination from OH airglow.

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• Difference and parameter analysis of LST inversion based on Landsat data

  WAN Ji-Kang, SHEN Zhe-Hui, LI Shan

  2024,43(2):225-233, DOI: 10.11972/j.issn.1001-9014.2024.02.012

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  The correct use of the product is possible only when the land surface temperature （LST） data is calculated by an accurate and reliable inversion algorithm. In this paper， we compare the inversion results of five commonly used LST inversion algorithms based on Landsat-8， Landsat-9 data， and weather station data. The inversion results and parameter sensitivity analysis of different algorithms are tested. The results show that the inversion results of the Radiative Transfer Equation （RTE） and Single Channel （SC） algorithms calculated based on land surface emissivity （LSE） are in good agreement with the ground measured. The inversion results of the SC algorithm based on the atmospheric water vapor inversion and the Split Window （SW） algorithm based on the atmospheric water vapor inversion are higher than the measured temperature. The inversion accuracy of the Mono Window （MW） algorithm based on average temperature parameters is not ideal. In addition， the consistency of the inversion temperature of the two data on different ground objects is compared. Our study can provide a reference for land surface temperature inversion based on Landsat-9 data.

• Spectrum selection and performance analysis for ship detection

  ZHANG Lei, QIAO Kai, HUANG Shi-Sheng

  2024,43(2):234-240, DOI: 10.11972/j.issn.1001-9014.2024.02.013

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  The detection of ships and other sea targets is of great significance to sea surface management， national defense security， search and rescue， and other fields. Space-borne infrared remote sensing has a wide coverage ， which is an effective means to achieve wide-area detection of ship targets. Affected by the diurnal cycle of the solar zenith angle， the temperature difference between the ship and the sea surface changes periodically， resulting in a thermal crossover period twice a day in the ship detection scene on the sea surface. In this paper， taking the mid-latitude summer and winter sea surface environment as an example， the 24-hour infrared radiation characteristics of the sea surface ship detection scene are established， and a multi-spectrum optimal combination scheme is proposed， which is realized by the detection of dual detection spectrum bands of 3.50 -4.10 μm and 10.25-10.75 μm day and night continuous observation with signal-to-noise ratio better than 15. The proposed dual-spectrum detection method provides technical support for the application of wide-area all-time sea surface target detection.

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Infrared Photoelectric Technology and Application

• Real time denoising method for spaceborne photon counting laser ranging radar

  TAN Chong-Tao, YU Wen-Bo, XIANG Yu-Yan, LI Shao-Hui, YU Jing, WANG Qian-Ying, LI Song

  2024,43(2):241-253, DOI: 10.11972/j.issn.1001-9014.2024.02.014

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  The spaceborne photon counting laser ranging radar system has significant advantages such as high repetition rate and high precision， but it also faces the problem of large amount of original data and high proportion of noise data. In order to adapt to the transmission capacity of the satellite data channel， it is necessary to compress the original data volume and ensure the recall rate of signal photons， so it is necessary to develop a hardware based real-time denoising algorithm. This article proposes a fast denoising algorithm that combines coarse and fine processing. Firstly， based on the laser emission pulse width， system noise rate， target characteristics， and local density information of received photon events， coarse denoising is performed to remove some noisy photons； then， using histogram statistics， fine denoising is performed on the retained photon events to determine the signal photon interval and the final signal photon and its time information. The algorithm is verified by Monte Carlo simulation and ICESat-2 measured data. The test results show that the recall ratio， precision ratio and harmonic average of the algorithm are more than 94%， 93% and 94% respectively， and the operational efficiency is improved by 10%. The algorithm can achieve fast and real-time denoising of photon events， providing a theoretical basis for real-time denoising processing of onboard hardware.

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• Gradient-aware channel attention network for infrared small target image denoising before detection

  LIN Zai-Ping, LUO Yi-Hang, LI Bo-Yang, LING Qiang, ZHENG Qing, YANG Jing-Yi, LIU Li, WU Jing

  2024,43(2):254-260, DOI: 10.11972/j.issn.1001-9014.2024.02.015

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  Infrared small target denoising is widely used in military and civilian fields. Existing deep learning-based methods are specially designed for optical images and tend to over-smooth the informative image details， thus losing the response of small targets. To both denoise and maintain informative image details， this paper proposes a gradient-aware channel attention network （GCAN） for infrared small target image denoising before detection. Specifically， we use an encoder-decoder network to remove the additive noise of the infrared images. Then， a gradient-aware channel attention module is designed to adaptively enhance the informative high-gradient image channel. The informative target region with high-gradient can be maintained in this way. After that， we develop a large dataset with 3981 noisy infrared images. Experimental results show that our proposed GCAN can both effectively remove the additive noise and maintain the informative target region. Additional experiments of infrared small target detection further verify the effectiveness of our method.

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• Chaotic and fractal characteristics of infrared electromagnetic wavefield in the media of atmosphere

  XU Wen-Jun, SUN Sheng-Li, LIU Gao-Rui

  2024,43(2):261-268, DOI: 10.11972/j.issn.1001-9014.2024.02.016

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  Chaotic dynamics is a significant systematic feature of infrared electromagnetic wavefields that requires further study. Understanding the chaotic dynamics of infrared radiation wavefields can lead to advancements in high-performance detection， imaging， and recognition of weak， moving， time-varying signals. To extract the time series of the dynamic system， we have established a 4D time-space observing system. We then use the FFT transform on a random time series of frequency-band infrared data to obtain the fractional Brownian motion dimension， indicating a fractal structure in the atmospheric infrared radiation wavefield. By using time-delay analysis， we construct a dimensional phase space and compute the fractal dimension. We also observe that the first Lyapunov exponent remains positive in different phase spaces， leading to the initial conclusion that the atmospheric infrared wavefield is chaotic. To measure the chaotic strength of real cases in the time-space domain， we use the permutation entropy. These results serve as a foundation for further research， such as understanding the dynamic evolution mechanism of moving objects and their background wavefields， capturing time-varying signals， and making long-term nonlinear predictions of infrared wave behaviors in different domains.

• Low noise ROIC integrated with correlated double sampling with adjustable intervals for hyperspectral applications

  WU Shuang, LIANG Qing-Hua, CHEN Hong-Lei, DING Rui-Jun

  2024,43(2):269-276, DOI: 10.11972/j.issn.1001-9014.2024.02.017

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  Low noise is a key requirement of readout integrated circuit （ROIC） in hyperspectral applications for its low radiation. Correlated double sampling （CDS） is commonly used to suppress noise. In this paper， CDS is improved by adjusting the time interval between the clamp and sample-and-hold （SH）， which can filter low-frequency noise flexibly. A 640×512， 15 μm pixel pitch ROIC is designed and fabricated in 180 nm CMOS process. The input stage consists of low-noise capacitive trans-impedance amplifier （CTIA） and CDS with adjustable intervals （AICDS）. A timing generator is proposed to extend the CDS reset time from 0 to 270 clock cycles. By extending the reset time to decrease the time interval， the noise electrons are significantly decreased from 39 e^- to 18.3 e^-. The SPECTRE simulation and the experimental results corroborate that the proposed structure AICDS can optimize noise performance of hyperspectral ROIC， thus can be widely used.

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Image Processing and Software Simulation

• Study of infrared radiation suppression on solid surfaces by spraying water film

  YANG Bin, LIU Zhi-Ling, HAN Lei, LI Zhi-Wei, WANG Zhen, AN Yi-Feng, HUANG Zhi-Feng

  2024,43(2):277-285, DOI: 10.11972/j.issn.1001-9014.2024.02.018

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  To investigate the mechanism of infrared radiation suppression on solid surfaces by spraying water film and to establish an accurate calculation method for infrared radiation， the theoretical and experimental research was conducted to study the influence of water film on the infrared radiation of solid surfaces. The results showed that in the 8-12 μm wavelength range， the infrared radiation characteristics of a solid surface covered with a water film （with a thickness greater than 100 μm） mainly relied on the infrared radiation emitted by the water film. An infrared radiation transfer model was developed to encompass solid surfaces covered by the water film， and the accuracy of commonly used calculation methods in the literature was analyzed. The error in calculating infrared radiation using the free surface temperature of the water film was less than 0.3%， while the maximum error in calculating infrared radiation using the temperature of the solid surface was 8.32%.

• A microscopic image enhancement method for cell experiments in space

  LI Yuan-Yuan, YUAN Yong-Chun, RUAN Li-Hua, ZHAO Qing-Qing, ZHANG Tao

  2024,43(2):286-292, DOI: 10.11972/j.issn.1001-9014.2024.02.019

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  High image quality is crucial for cell experiments in space， as it requires the ability of remotely monitoring to grasp the progress and direction of experiments. However， due to space limitations and environmental factors， imaging equipment is strongly constrained in some performance， which directly affects the imaging quality and observation of cultivated targets. Moreover， experimental analysis on the ground requires tasks such as feature extraction and cell counting， but uneven lighting can seriously affect computer processing. Therefore， a method called STAR-ADF is proposed， and experimental results show that the proposed method can effectively remove noise， equalize illumination， and increase the enhancement evaluation index by 12.5% in comparison with original figures， which has certain robustness.

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遥感技术与应用

• A simplified parameterization scheme of mid-infrared radiative transfer for satellite remote sensing

  YAO Qian, XU Hua, FAN Cheng, LI Li, WANG Si-Heng, ZHENG Yang, XU Wen-Bin, HOU Wei-Zhen, XU Jing-Hai, ZHUANG Qi-Feng, ZHOU Peng, ZHANG Hao, CHEN Zhen-Ting, LI Zheng-Qiang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

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  As the connecting spectral band of visible-near infrared and thermal infrared， mid-infrared （MIR） combines the reflective characteristics of short-wave radiation and the emissive characteristics of long-wave radiation， which is of great importance for application scenarios such as temperature detection and target identification. At present， the radiative transfer （RT） calculation of the MIR spectrum still faces the problem of many input background parameters which are not easy to obtain. Based on this， a simplified parameterization scheme of MIR RT for satellite remote sensing is proposed. Using the MODTRAN model （MM）， the background surface and atmospheric parameters involved in the MIR daytime RT process were quantitatively simulated and analyzed to obtain the key parameters affecting RT， from which an MM-based parameter simplified scheme （SS） was developed. The total radiance calculated by SS and MM is compared and validated at the center wavelength of 6 MIR channels of MODIS， and the RMSE is less than 0.004399 with high accuracy. The SS only relies on surface temperature， surface emissivity， atmospheric profile type， water vapor and cloud optical thickness， and does not require input of aerosol， CO₂ and O₃ data. Compared with the MM， the SS reduces the input parameters from 8 categories to 5 categories， and the calculation time efficiency increases by 9.02%. With limited computational resources， the SS proposed in this paper can provide support for the application areas such as fast processing of MIR images and remote sensing simulation of large scenes.

图像处理及软件仿真

• Modified Multiple-Component Scattering Power Decomposition for PolSAR Data based on Eigenspace of Coherency Matrix

  ZHANG Shuang, WANG Lu, WANG Wen-Qing

  DOI:

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  A modified multiple-component scattering power decomposition for analyzing polarimetric synthetic aperture radar (PolSAR) data is proposed. The modified decomposition involves two distinct steps. Firstly, eigenvectors of the coherency matrix are used to modify the scattering models. Secondly, the entropy and anisotropy of targets are used to improve the volume scattering power. With the guarantee of high double-bounce scattering power in the urban areas, the proposed algorithm effectively improves the volume scattering power of vegetation areas. The efficacy of the modified multiple-component scattering power decomposition is validated using actual AIRSAR PolSAR data. The scattering powers obtained through decomposing the original coherency matrix and the coherency matrix after orientation angle compensation are compared with three algorithms. Results from the experiment demonstrate that the proposed decomposition yields more effective scattering powers for representing the PolSAR data set.

红外材料与器件

• A Monolithic Integrated Medium Wave Mercury Cadmium Telluride Polarimetric Focal Plane Array

  CHEN Ze-Ji, HUANG You-Wen, PU En-Xiang, XIAO Hui-Shan, XU Shi-Chun, QIN Qiang, KONG Jin-Cheng

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  Abstract: (28) HTML (0) PDF (2.29 MKB)(15)

  Abstract:

  A medium wave (MW) 640×512 (25 μm) Mercury Cadmium Telluride (HgCdTe) polarimetric focal plane array (FPA) was demonstrated. The micro-polarizer arrays (MPA) has been carefully designed in terms of line grating structure optimization and crosstalk suppression. A monolithic fabrication process with low damage was explored, which was verified to be compatible well with HgCdTe devices. After monolithic integration of MPA, NETD < 9.5 mK was still maintained. Furthermore, to figure out the underlying mechanism that dominates extinction ratio (ER), specialized MPA layouts were designed, and the crosstalk was experimentally validated as the major source that impacts ER. By expanding opaque regions at pixel edges to 4 μm, crosstalk rates from adjacent pixels can be effectively reduced to approximately 2%, and promising ERs ranging from 17.32 to 27.41 were implemented.

• Optical facet coatings for high-performance LWIR quantum cascade lasers at λ ～ 8.5 μm

  MA Yuan, LIN Yu-Zhe, WAN Chen-Yang, WANG Zi-Xian, ZHOU Xu-Yan, ZHANG Jin-Chuan, LIU Feng-Qi, ZHENG Wan-Hua

  DOI:

  Abstract: (29) HTML (0) PDF (1.46 MKB)(16)

  Abstract:

  We report on the performance improvement of long-wave infrared quantum cascade lasers （LWIR QCLs） by studying and optimizing the anti-reflection （AR） optical facet coating. Compared to Al₂O₃ AR coating， the Y₂O₃ AR coating exhibits higher catastrophic optical mirror damage （COMD） level， and the optical facet coatings of both material systems have no beam steering effect. A 3-mm-long cavity length， 9.5-μm-wide buried heterostructure （BH） LWIR QCL of λ ~ 8.5 μm with Y₂O₃ metallic high-reflection （HR） and AR of ~ 0.2 % reflectivity coating demonstrates a maximum pulsed peak power of 2.19 W at 298 K， which is 149% higher than that of uncoated device. For continuous-wave （CW） operation， by optimizing the reflectivity of the Y₂O₃ AR coating， the maximum output power reaches 0.73 W， which is 91% higher than the uncoated device.

• Investigation on p-type doping of PBn unipolar barrier InAsSb photodetectors

  Zhang Jian, Chang Chao, Li Hong-Fu, Shi Yu-Na, Yin Han-Xiang, Li Yan-Hui, Yue Biao, Wang Hai-Peng, Yan Chang-Shan, Dai Xin-Ran, Deng Gong-Rong, Kong Jin-Cheng, Zhao Peng, Zhao Jun

  DOI:

  Abstract: (45) HTML (0) PDF (1.69 MKB)(17)

  Abstract:

  The lattice-matched XBn structures of InAsSb， grown on GaSb substrates， exhibit high crystal quality， and can achieve extremely low dark current at high operating temperatures （HOT）. Its superior performance is attributed to the unipolar barrier， which blocks the majority carriers while allowing unhindered hole transport. To further explore the energy band and carrier transport mechanisms of the XBn unipolar barrier structure， this paper systematically investigates the influence of doping on the dark current， photocurrent， and tunneling characteristics of InAsSb photodetectors in the PBn structure. Three high-quality InAsSb samples with unintentionally doped absorb layers （AL） were prepared， with varying p-type doping concentrations in the GaSb contact layer （CL） and the AlAsSb barrier layer （BL）. As the p-type doping concentration in the CL increased， the device’s turn-on bias voltage also increased， and p-type doping in the BL led to tunneling occurring at lower bias voltages. For the sample with UID BL， which exhibited extremely low dark current 5×10^-6 A/cm². The photocurrent characteristics were well-fitted using the back-to-back diode model， revealing the presence of two opposing space charge regions on either side of the BL.

• 1280×1024 dual-color mid-wavelength infrared InAs/GaSb superlattice focal plane arrays

  BAI Zhi-Zhong, HUANG Ming, XU Zhi-Cheng, ZHOU Yi, LIANG-Zhao Ming, YAO Hua-Cheng, CHEN Hong-Lei, DING Rui-Jun, CHEN Jian-Xin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (37) HTML (0) PDF (992.07 KKB)(26)

  Abstract:

  In this paper， we report research results of 1280×1024 dual-color mid-wavelength infrared InAs/GaSb superlattice focal plane arrays. The detector structure is PN-NP epitaxial multilayer and the signal is read out by sequential mode. The superlattice structure was grown on GaSb substrate using molecular beam epitaxy （MBE） technology. The respective structure of each absorption region are Mid-Wavelength 1（MW1）： 6ML （ InAs） /7ML （ GaSb） and Mid-Wavelength 2 （MW2） ： 9ML （ InAs） /7ML （ GaSb）. The pixel center distance of the detector is 12μm. At 80 K measurement， the detector has spectral response wavelength of 3-4μm and 3.8-5.2μm respectively； The MW1 detector has a peak detectivity of 6.32×10¹¹cmHz^1/2W^-1； The MW2 detector has a peak detectivity of 2.84×10¹¹cmHz^1/2W^-1.Infrared images of both wavebands have been taken using infrared imaging test by adjusting devices voltage bias. Its the first time 1280 × 1024 InAs/GaSb Type II superlattice mid-wave length two-color infrared focal plane detector has been reported in China.

红外及光电技术与应用

• Characteristics analysis of 1.06 μm long-cavity diode lasers based on asymmetric waveguide structures

  ZHAO Ren-Ze, GAO Xin, FU Ding-Yang, ZHANG Yue, SU Peng, BO Bao-Xue

  DOI:

  Abstract: (98) HTML (0) PDF (857.88 KKB)(19)

  Abstract:

  In long-cavity edge-emitting diode lasers, longitudinal spatial hole burning (LSHB), two-photon absorption (TPA) and free carrier absorption (FCA) are among the key factors that affect the linear increase in output power at high injection currents. In this paper, a simplified numerical analysis model is proposed for 1.06 μm wavelength long-cavity diode lasers by combining TPA and FCA losses with one-dimensional (1D) rate equations. The effects of LSHB, TPA and FCA on the output characteristics are systematically analyzed, and it is proposed that adjusting the front facet reflectivity and the position of the quantum well (QW) in the waveguide layer can improve the front facet output power.

太赫兹与毫米波技术

• The physical model， structural fabrication， and DC testing of lateral gate transistor terahertz detectors

  KANG Ya-Ru, DONG Hui, LIU Jing, HUANG Zhen, LI Zhao-Feng, YAN Wei, WANG Xiao-Dong

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (119) HTML (0) PDF (994.57 KKB)(20)

  Abstract:

  For the high-electron-mobility transistor（HEMT） terahertz detector with a side-gate structure， a physical model for DC transport and terahertz detection of the device was constructed. Using a self-alignment process， well-shaped and reliable contacts for the side-gate structure were successfully fabricated， effectively solving contact issues between the dual gates and the mesa. Ultimately， terahertz detectors with different gate widths（200 nm， 800 nm， and 1400 nm） of side-gate GaN/AlGaN HEMTs were obtained. DC tests revealed a clear linear relationship between the gate width of different devices and their threshold voltage， confirming the DC transport model of the side-gate HEMT terahertz detector. These results provide experimental verification and guidance for the theoretical model of the complete side-gate HEMT terahertz detector， offering significant support for the development of side-gate HEMT terahertz detectors.

红外材料与器件

• Mid-wavelength infrared nBn photodetectors based on InAs/InAsSb type-II superlattice with an AlAsSb/InAsSb superlattice barrier

  SHAN Yi-Fan, WU Dong-Hai, XIE Ruo-Yu, ZHOU Wen-Guang, CHANG Fa-Ran, LI Nong, WANG Guo-Wei, JIANG Dong-Wei, HAO Hong-Yue, XU Ying-Qiang, NIU Zhi-Chuan

  DOI:

  Abstract: (70) HTML (0) PDF (1017.36 KKB)(15)

  Abstract:

  InAs/InAsSb type-II superlattice （T2SL） materials hold great promise for the development of mid-wavelength infrared photodetectors operating at high temperatures， as they avoid the defects caused by Ga atoms in InAs/GaSb T2SL and exhibit long minority carrier lifetime. To reduce dark current， minority carrier unipolar barrier structures， such as nBn detectors， are commonly employed. In mid-wavelength infrared InAs/InAsSb T2SL nBn photodetectors， multielement alloy such as AlAsSb is typically utilized as the barrier layer to block the transport of majority carriers. However， the small valence band offset （VBO） between the barrier and absorption layers leads to the saturation of photocurrent at high bias voltage， resulting in increased dark current. In this work， an AlAsSb/InAsSb T2SL barrier was designed to eliminate the VBO and reduce the bias dependency of quantum efficiency. The results show that the fabricated nBn photodetector exhibits a 50% cutoff wavelength of 4.5 μm at 150K. The optical response of the photodetector saturates under a small bias of -50 mV， achieving a peak responsivity of 1.82 A/W at 3.82 μm and a quantum efficiency of 58.8%. At 150 K and -50 mV applied bias， the photodetector exhibits a dark current density of 2.01×10^-5 A/cm² and a specific detectivity of 6.47×10¹¹ cm·Hz^1/2/W.

太赫兹与毫米波技术

• An improved ASM-HEMT model for kink effect on GaN devices

  WANG Shuai, CHENG Ai-Qiang, GE Chen, CHEN Dun-Jun, LIU Jun, DING Da-Zhi

  DOI:

  Abstract: (26) HTML (0) PDF (1.80 MKB)(14)

  Abstract:

  With the analysis of experiment and theory on GaN HEMT devices under DC sweep， an improved model for kink effect based on ASM-HEMT is proposed， considering the relationship between the drain/gate-source voltage and kink effect. The improved model can not only accurately describe the trend of the drain-source current with current collapse and kink effect， but also precisely fit different values of drain-source voltages at which kink effect occurs under different gate-source voltages. Furthermore， it well characterizes the DC characteristics of GaN devices in the full operating range， with the fitting error less than 3%. To further verify the accuracy and convergence of the improved model， a load-pull system is built in ADS. The simulated result shows that although both the original ASM-HEMT and the improved model predict the output power for maximum power matching of GaN devices well， the improved model predicts the power-added efficiency for maximum efficiency matching more accurately， with 4% improved.

红外材料与器件

• Research on Silicon Avalanche Photodetector with Wideband Response

  PENG Hong-ling, WEI Jia-Qi, SONG Chun-Xu, WANG Tian-Cai, CAO Peng, DENG Jie, CHEN Jian, Qian-Dong Zhuang, ZHENG Wan-Hua

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (25) HTML (0) PDF (1.02 MKB)(13)

  Abstract:

  Based on the current application requirements for wideband response photodetectors, we designed a novel silicon avalanche photodetector (Si APD) offers high response in a broad spectral range of 250 -1100 nm and is capable of achieving efficient detection of three bands of ultraviolet, visible and near-infrared light without the need of splicing. The enhancement of ultraviolet and infrared band of silicon were separately analyzed. This was followed by simulation on the device structure designs using different methods such as back incidence, to improve short wavelength absorption while maintaining a high infrared absorption. The Si APD shows a peak wavelength at around 940 nm and a high photoresponse at 250 nm and 1100 nm which exceed 15% of the peak responsivity. This type of device is suitable for multispectral applications and future high-precision detection.

图像处理及软件仿真

• Research on fast detection method of infrared small targets under resource-constrained conditions

  Zhang Rui, Liu Min, Li Zheng

  DOI:

  Abstract: (67) HTML (0) PDF (1.33 MKB)(16)

  Abstract:

  Infrared small target detection is a common task in infrared image processing， and computational resources are limited in application scenarios that require the use of the infrared small target detection. Traditional IR small target detection methods face the problem of balancing detection rate and accuracy. This paper presents a swift infrared small target detection method designed for resource-constrained conditions， in the YOLOv5s model that adds a tiny target detection head and replaces the original Intersection over Union （IoU） with a Normalized Gaussian Wasserstein Distance （NWD）， considering both the detection accuracy and rate of the infrared targets. The experimental results show that the algorithm in this paper realizes the maximum 95 FPS effective detection speed of the infrared small targets on a 15W TPU， and at the same time achieves the maximum 91.9 AP@0.5 effective detection accuracy， which effectively improves the detection efficiency of the infrared small targets under resource-constrained conditions.

红外材料与器件

• Characterization of 2 μm band soliton optical comb based on silicon nitride microcavity

  CHENG Ru-Min, SUN Jia-Hao, WU Jia-Gui, GUO Deng-Ji, XU Jiao, YANG Jun-Bo, YAN Pei-Guang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (99) HTML (0) PDF (2.53 MKB)(14)

  Abstract:

  The optical frequency combs（OFCs） generation of silicon nitride microcavities in the 2 μm band is investigated. Dispersion modulation of silicon nitride waveguides is carried out by geometrical design， appropriate bus waveguide dimensions are selected， and the thermal refraction noise of silicon nitride microcavities at different modulation frequencies is discussed from the thermal absorption theory. The nonlinear Schr?dinger equation is used as the basic model to study the evolution of the cavity under different dispersion effects. The numerical results show that silicon nitride is able to observe the hysteretic state transition of the system， i.e.， the relaxation oscillation phenomenon during the transition of the system to the stable domain， more clearly in the 2 μm band， and at the same time， the cavity is able to transition to the steady state soliton faster under the action of the higher-order dispersion， which provides a scheme to study the respiratory soliton.

太赫兹与毫米波技术

• Simulation analysis of the radiation terahertz wave characteristics of photoconductive antenna materials

  HOU Lei, WU Xiao-Bo, YANG Lei, SHI Wei, HANG Yu-Hua

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (29) HTML (0) PDF (869.86 KKB)(15)

  Abstract:

  The photoconductive antenna is a kind of widely used broadband terahertz (THz) radiation source in THz time-domain spectroscopy systems, and the substrate material of the antenna is crucial for the characteristics of generated THz wave. The widely used photoconductive antenna material is the second generation semiconductor of GaAs, while the third-generation semiconductor has a larger band gap, which is more advantageous for improving the power of THz wave from photoconductive antenna. In this work, the current surge model of large-aperture photoconductive antennas was used to simulate the characteristics of THz waves radiated by photoconductive antenna made by commonly used SI-GaAs and LT-GaAs, and the third-generation semiconductors (ZnSe, GaN, SiC) that are expected to be used in the future for photoconductive antennas. The results show that under the same bias electric field and their respective highest pump laser flux, LT-GaAs antenna generates the THz waves with the highest amplitude and widest frequency. The photoconductive antenna made by third-generation semiconductor materials can withstand higher bias electric fields, and the intensity of radiated THz waves is much greater than that from GaAs antennas under their respective maximum bias electrical fields. This work provides theoretical guidance for the development of new third-generation semiconductor photoconductive antennas.

• Preparation of flexible low-loss ABS/Ag-coated terahertz hollow waveguide by plasma treatment and study on its transmission reliability

  LIU Sheng, SHEN Yuan-Jie, HOU Guang-Ning, ZHA Zhi-Peng, ZHU Yi-Zhen, YU Shuo-Ying, ZHANG Qing-Tian, ZHAO Qiang, LIU Shao-Hua, JING Cheng-Bin, CHU Jun-Hao

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (30) HTML (0) PDF (1.71 MKB)(8)

  Abstract:

  The performance of the ABS/Ag-coated terahertz hollow waveguide （HWG） was improved through plasma treatment of the ABS structural tube. The adhesion of the silver （Ag） film to the ABS tube was enhanced from level 5 to level 2 after plasma treatment. The 4.2 mm bore waveguide sample treated with plasma has a more uniform and denser silver film than the untreated sample， which contributes to the reduction of transmission losses from 0.72 to 0.70 dB/m at 0.3 THz and 1.47 to 1.44 dB/m at 0.1 THz， respectively. After 200 hours of hydrothermal aging and 16 cycles of high and low temperature cycling testing， the straight loss of the HWG sample treated with plasma increased by less than 0.1 dB/m， while the untreated sample underwent an increase of more than 1.0 dB/m. The results indicate that the ABS/Ag-coated HWG fabricated by plasma treatment has lower loss， higher reliability and better anti-aging performance compared with the untreated sample. It can be potentially used for establishment of next-generation communication， sensing， and THz imaging systems.

红外材料与器件

• Structural design of mid-infrared waveguide detectors based on InAs/GaAsSb superlattice

  PEI Jin-Di, CHAI Xu-Liang, WANG Yu-Peng, ZHOU Yi

  DOI:

  Abstract: (99) HTML (0) PDF (1.56 MKB)(20)

  Abstract:

  In the realm of near-infrared spectroscopy， the detection of molecules has been achieved using on-chip waveguides and resonators. In the mid-infrared band， the integration and sensitivity of chemical sensing chips are often constrained by the reliance on off-chip light sources and detectors. In this study， we demonstrate an InAs/GaAsSb superlattice mid-infrared waveguide integrated detector. The GaAsSb waveguide layer and the InAs/GaAsSb superlattice absorbing layer are connected through evanescent coupling， facilitating efficient and high-quality detection of mid-infrared light with minimal loss. We conducted a simulation to analyze the photoelectric characteristics of the device. Additionally， we investigated the factors that affect the integration of the InAs/GaAsSb superlattice photodetector and the GaAsSb waveguide. Optimal thicknesses and lengths for the absorption layer are determined. When the absorption layer has a thickness of 0.3μm and a length of 50μm， the noise equivalent power reaches its minimum value， and the quantum efficiency can achieve a value of 68.9%. The utilization of waveguide detectors constructed with III-V materials offers a more convenient means of integrating mid-infrared light sources and achieving photoelectric detection chips.

• Application of principal component analysis and clustering methods in the discrimination of parameters in HgCdTe crystals

  WU Jia-Hao, QIAO Hui, LI Xiang-Yang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (86) HTML (0) PDF (1.07 MKB)(15)

  Abstract:

  A method for selecting parameters in HgCdTe crystals has been proposed， utilizing Principal Component Analysis （PCA） and clustering methods， with the establishment of a data model for screening the parameters of HgCdTe crystals. Within the model， initial crystal data undergoes a cleaning and analysis process. PCA is employed for dimensionality reduction， and the Density-Based Spatial Clustering of Applications with Noise （DBSCAN） algorithm is used to identify the densest regions within the crystal data. Furthermore， high-performance chip data， obtained post-processing， is utilized to fit boundary ellipses for high-quality HgCdTe crystal parameters. These ellipses act as criteria for identifying high-quality crystals. Capable of generating crystal ratings based on input electrical and optical parameters， the model achieves a coverage rate exceeding 90%.

太赫兹与毫米波技术

• Terahertz imaging super-resolution algorithm based on spatial curve filling

  YANG Mo-Xuan, ZHAO Yuan-Meng, LIU Hao-Xin, LIU Yi, WU You, ZHANG Cun-Lin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (99) HTML (0) PDF (1.36 MKB)(15)

  Abstract:

  The performance of radiation sources and detectors currently limits terahertz imaging technology， which still requires further improvement in terms of detail resolution， imaging speed， and noise suppression. This paper proposes a terahertz image super-resolution algorithm based on spatial curve filling. The ViT （Vision Transformer） structure backbone network is utilized to extract terahertz image features through an attention mechanism. A Hilbert spatial curve is constructed to reconstruct the image according to the feature map using the curve filling method. Lightweight one-dimensional convolution processing is used for reconstructing image features， while inverse transformation of reconstructed maps restores the image"s spatial structure. Finally， pixel reorganization enables upsampling to obtain an output image with enhanced object contour and details. Experimental results show that compared with conventional ViT structures， this proposed method improves Peak Signal-to-Noise Ratio （PSNR） by 0.81 dB and Structural Similarity Index （SSIM） by 0.0074 effectively suppressing noise influence on texture while significantly improving resolution resulting in images with improved quality.

红外及光电技术与应用

• Miniaturized Microchip Array Passive Q-Switched Solid-State Laser

  WANG Zhen, ZHAO Bai-Qing, LI Jia-Geng, HAN Qin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (21) HTML (0) PDF (956.36 KKB)(19)

  Abstract:

  To address the spatial constraints in unmanned aerial vehicle target detection systems， a scheme for a multi-beam scanning passively Q-switched microchip array solid-state laser was proposed. This system utilizes a six-core semiconductor laser array to compactly pump a strip-shaped Nd：YAG/Cr⁴⁺：YAG bonded crystal. At a pumping power of 1.6W per path， it generates six output laser beams with a wavelength of 1064.4nm， pulse width of 2.4ns， beam quality of 1.39， peak power of 3.75kW， and a repetition frequency up to 22kHz. The entire system"s volume is only 2cm × 2cm × 1.5cm， and achieves simultaneous output of six laser paths. The study investigated the impact mechanism of the initial transmittance of the Q-switching crystal and the reflectivity of the output mirror on the laser pulse repetition frequency and peak power， with a particular focus on the uniformity of the laser output from the pump source cores. The feasibility of using a single laser-bonded crystal to produce multiple narrow pulse laser beams in the nanosecond range was experimentally verified. The research results demonstrate the miniaturized structure"s ability to achieve multi-beam emission from a passively Q-switched solid-state laser， providing insights for the miniaturization and integration of laser sources in detection systems.

图像处理及软件仿真

• Pixel gradient-based adaptive iterative median filter for image impulse noise removal

  JIN Xiang-Bo, WANG Yue-Ming

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (70) HTML (0) PDF (3.34 MKB)(118)

  Abstract:

  Image impulse noise removal is essential for obtaining high-quality images. A novel pixel gradients-based adaptive iterative median filter is proposed to remove image impulse noise by utilizing the principles of thermal infrared camera imaging. Firstly， the maximum pixel gradient of the original image is computed based on the camera"s modulation transfer function （MTF）， and a corresponding set of pixel gradients is established. Subsequently， the gradient weight root-mean-square error （GWRMSE） set of the original image and the corresponding pixel gradient filtered image is computed， and the optimal pixel gradient is determined as the one corresponding to the maximum value of Gaussian distribution of the GWRMSE set. Finally， the adaptive window size and number of iterations for the proposed filter are determined according to the density and complexity of the impulse noise in the image. Extensive experimental results demonstrate that the proposed filter exhibits excellent robustness in removing 8-bit and 16-bit single-channel impulse noise images. In comparison with other state-of-the-art methods， the proposed method can remove low-density random-valued impulse noise （RVIN） and salt-and-pepper noise （SAPN） in real thermal infrared camera-acquired images in real-time while preserving more than 99.5% of original pixels during the noise removal process. Additionally， for high-density SAPN removal， the proposed method achieves competitive results， demonstrating better peak signal-to-noise ratio （PSNR） and structural similarity index （SSIM） in comparison with filtering methods of faster running time and faster execution time in comparison with denoising methods of superior PSNR and SSIM. Moreover， it can recover meaningful image details even for images severely damaged by extreme SAPN （99%）.

遥感技术与应用

• Noise model of oceanic spaceborne photon counting lidar

  YANG Jian, MA Yue, YU Wen-Bo, LI Shao-Hui, YU Jing, WANG Qian-Yin, LI Song

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (45) HTML (0) PDF (1.08 MKB)(160)

  Abstract:

  With the advantage of high sensitivity and high repetition rate， spaceborne photon counting lidar has shown great application in ocean areas. The photon counting detector can not only respond to the weak echo signal， but is also susceptible to solar radiation. Due to the great impact of background noise on the performance of lidar systems， as well as the impact on the data volume， accurate estimation of noise level is crucial in the design of satellite lidar systems. A noise model of oceanic spaceborne photon counting lidar was proposed that considers the contribution of the atmosphere， water surface， and water column. By inputting the system parameters of the new generation photon counting lidar ATLAS and the environmental parameters， the MAPEs （mean absolute percentage errors） between estimated noise and the ATLAS measured noise are within 15%， which confirms the effectiveness of the noise model.

• Arctic sea surface CO₂ partial pressure based on LiDAR

  ZHANG Si-Qi, CHEN Peng, ZHANG Zhen-Hua, PAN De-Lu

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (29) HTML (0) PDF (1.67 MKB)(154)

  Abstract:

  The spaceborne light detection and ranging （LiDAR）， as a novel active remote sensing technology， offers possibilities for global diurnal research. In this study， global sea surface chlorophyll-a （Chla） concentrations were inverted using satellite data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations （CALIPSO）. A feedforward neural network model based on LiDAR data （FNN-LID） was developed to reconstruct a long-term diurnal dataset of sea surface pCO₂ in the Arctic Ocean. Subsequently， verification and analysis were conducted on the polar sea surface Chla concentrations and sea surface pCO₂ based on active remote sensing. The results demonstrated that the inversion products generated by this algorithm exhibit high data quality and exhibit favorable consistency with both other passive remote sensing products and buoy observations. Moreover， these products effectively fill data gaps during polar winters. Along the Arctic Ocean， margin seas significantly influenced by terrestrial sources consistently display high sea surface Chla concentrations. The spatial distribution of sea surface pCO₂ in the Arctic Ocean manifests meridional variations， with marked seasonal fluctuations， even higher than 80 μatm. Over the past two decades， the Arctic Ocean has consistently acted as a carbon dioxide sink， while areas with substantial sea ice decline such as the East Siberian Sea and Kara Sea exhibit pronounced increases in sea surface pCO₂.

红外材料与器件

• The scanning tunneling spectra of Hg_0.72Cd_0.28Te and the model interpretation

  XIAO Zheng-Qiong, DAI Hao-Guang, LIU Xin-Yang, CHEN Ping-Ping, ZHA Fang-Xing

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (45) HTML (0) PDF (1.37 MKB)(98)

  Abstract:

  The cross-sectional scanning tunneling microscopy （XSTM） technique was used to study the cleaved surface of Hg_0.72Cd_0.28Te grown by molecular beam epitaxy. Scanning tunnel spectroscopy （STS）’s measurements show that the width of zero current plateau （the apparent tunneling gap） of current-voltage （I/V） spectra is about 130% larger than the practical band gap of the material， implying the existence of obvious tip-induced band bending （TIBB） effect with the measurement. Based on the 3D TIBB model， the STS data can however be interpreted and the calculated I/V spectra are in good agreement with the measurement. Nevertheless， certain deviation appears for those I/V data which were acquired with a large imaging bias. This is because the current TIBB model does not take into account the transport mechanism of the material itself， for which the band-to-band tunneling， trap assisted tunneling etc. could be non-negligible factors for the tunneling.

红外及光电技术与应用

• Visible-NIR-II dual-channel fluorescence imaging system

  LIU Wen, NI Hu-Wei, QIAN Jun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (33) HTML (0) PDF (1.37 MKB)(137)

  Abstract:

  A dual-channel macroscopic imaging system has been developed based on optical methods, which can simultaneously capture the visible light and near-infrared second window (NIR-II) fluorescence. It could provide high-quality bright-field real-time images with the NIR-II fluorescence information, addressing the significant disparity issue between fluorescence and bright-field images in conventional NIR-II macroscopic imaging systems. In the experiment, the anti-scattering capability and imaging performance of NIR-II fluorescence signals of indocyanine green (ICG) were tested using different thicknesses of adipose tissues in the band of 1100-1700 nm and 1300-1700 nm respectively. Subsequently, the dual-channel macroscopic imaging system was used to obtain lymph node images of mouse and rat models, simulating the lymph node resection surgery and mimicking the process of abdominal lymph node clearance. Finally, different thicknesses of biological adipose tissues were added to the rat model to simulate the presence of adipose tissues covering the lymph nodes during actual surgery, and the penetration capability of the dual-channel system was observed. The visible and near-infrared second window dual-channel fluorescence imaging system provided the intuitive visual information to the operator, reducing surgery time and improving the patient prognosis, and held great potential for application in clinical surgical navigation.

太赫兹与毫米波技术

• Metal microstrip line defect detection of chip based on THz-TDR technology

  XU Zhen, XU De-Gang, LIU Long-Hai, LI Ji-Ning, ZHANG Jia-Xin, WANG Tan, REN Xiang, QIAO Xiu-Ming, JIANG Chen

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (59) HTML (0) PDF (3.58 MKB)(108)

  Abstract:

  The current main detection methods for packaging chip defects with small size， dense wiring， and high integration have drawbacks such as low accuracy and long cycle time. To compensate for the shortcomings of traditional detection methods， this study combines terahertz technology with time-domain reflection technology to explore the feasibility of detecting metal wire defects on chips. Firstly， different proportions of convex defects and concave defects were processed on metal microstrip lines of different widths to simulate incomplete opening/short circuits of metal wires in integrated chips. The time-domain reflection signals were collected using a terahertz time-domain reflectometer. Then， qualitative analysis was conducted on different defect degrees and types based on the corresponding time of time-domain reflection pulses， and the defect positions of the metal wires on the chip were accurately calculated. Finally， the finite element analysis method was used to simulate and analyze the metal wires with defects on the silicon substrate， which showed perfect consistency with the experimental results. This research shows that the combined terahertz technology with time-domain reflection technology can achieve the diagnosis and detection of metal wire defects on chips， providing an empirical reference for defect detection in integrated chips.

红外材料与器件

• Improved liquid phase epitaxy method for in-situ growth of HgCdTe with positive composition gradient

  HUO Qin, HAN Hong-Qiang, ZHANG Cheng, JIAO Cui-Ling, WANG Reng, MAO Cheng-Ming, LU Ye, CHEN Xin-Tian, QIAO Hui, LI Xiang-Yang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (68) HTML (0) PDF (946.55 KKB)(137)

  Abstract:

  The influence of growth conditions of liquid phase epitaxy on the composition gradient of HgCdTe was studied， and the growth model of liquid phase epitaxy （LPE） of HgCdTe was established. HgCdTe with positive composition gradient was grown by slider liquid phase epitaxy by changing the mercury loss rate. The positive composition gradient structure of HgCdTe grown under the growth condition of specific mercury loss was confirmed by corrosion thinning spectrum and secondary ion mass spectrometry （SIMS）. The experimental results show that the HgCdTe with positive composition gradient had the similar surface morphology and infrared transmission spectrum curve to the traditional HgCdTe with negative composition gradient； and it had high crystal quality， with a full width at half maximum （FWHM） of X-ray diffraction（XRD）double-crystal rocking curve of 28.8 arcsec.

红外及光电技术与应用

• Design and fabrication of an ultra-broadband dichroic beam-splitter with low polarization

  YU Tian-Yan, QIN Yang, JIANG Lin, DUAN Wei-Bo, LIU Ding-Quan

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (26) HTML (0) PDF (1.49 MKB)(121)

  Abstract:

  This paper describes the design and fabrication of one kind of dichroic beam-splitter that operates in an ultra-broadband spectral range from visible to longwave infrared regions simultaneously. The use of metal-dielectric coatings makes it implement structures that transmit the visible/near infrared radiation from 0.4 to 1.05 μm and reflect infrared radiation from 1.36 to 13 μm. At the same time， the structures are designed to obtain a low linear polarization sensitivity （Lps） in the visible/near infrared region. The transmission of visible/near infrared region is more than 85% and the average reflection of infrared region is more than 90%. The LPS of the region 0.4~1.05 μm is less than 4%.

太赫兹与毫米波技术

• Development of a homodyne mixing system for performance characterization of terahertz superconducting KIDs

  ZHANG Jia-Wen, JIN Jun-Da, SHI Sheng-Cai, LI Jing, GENG Wei, LYU Wei-Tao, LI Zhi, ZHI Qiang, PENG Zhao-Hang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (59) HTML (0) PDF (2.58 MKB)(152)

  Abstract:

  The homodyne mixing system is used to characterizing the performance of terahertz superconducting kinetic inductance detectors （KIDs）. However， homodyne mixing systems still have issues such as mixer imbalance， measurement system integration， and interference signals. The author designed a new single channel homodyne mixing hardware system and software algorithms to achieve integration of the measurement system， calibration of IQ-mixer imbalance， and performance characterization of KID； Furthermore， noise measurement of KIDs in VNA （vector network analyzer） CW mode is achieved； Finally， the method of hardware circuit design by dual channel homodyne mixing system based on autocorrelation algorithm effectively suppresses interference signals. It is worth noting that these research results are applied to characterize the performance of KIDs， which is important in the design of KIDs arrays.

红外材料与器件

• Characterization of visible-mid-infrared supercontinuum spectrum based on sandwiched silicon nitride waveguide

  SUN Jia-Hao, CHENG Ru-Min, GUO Kai, YIN Jin-De, QING Du-An, LI Ling, YAN Pei-Guang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (102) HTML (0) PDF (1.17 MKB)(140)

  Abstract:

  This paper introduces a low-thickness sandwich waveguide structure comprising silicon nitride -sapphire -silicon nitride layers. By exploiting its dispersion wave radiation effect and mid-infrared phase matching condition， combined with the waveguide pulse transmission model， this study examines the impact of different physical sizes of the sandwich waveguide on the phase matching point and spectral broadening. Through numerical simulation， a supercontinuum spectrum ranging from 0.5 to 4 μm is generated， producing a farther mid-infrared dispersion wave at a -40 dB level. Moreover， this model provides an in-depth mechanism for nonlinear waveguide pulse transmission. Theoretical analysis reveals that modifying the physical size of the silicon nitride and sapphire interlayer and altering the phase-matching conditions can regulate the position of the dispersion wave across a broader wavelength range.

太赫兹与毫米波技术

• Non-destructive thickness measurement with micron level accuracy based on a 4.3-THz quantum-cascade laser

  LI Hong-Yi, TAN Zhi-Yong, WAN Wen-Jian, CAO Jun-Cheng

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (61) HTML (0) PDF (1.15 MKB)(92)

  Abstract:

  A homodyne detection system to acquire the thickness of silicon wafers is constructed and described. By harnessing the relationship between the transmission phase change of a 4.3-THz light beam and the incident angle controlled by a mechanical rotating stage， the thickness value of sample can be precisely deduced using the standard residual error method. The results indicate that the fitted thickness of the sample differs by only 2.5~3 μm from more accurate results measured by optical microscopes， achieving terahertz non-destructive thickness measurement with micron level accuracy. The experiment validates the effectiveness of terahertz quantum-cascade laser in non-contact and nondestructive measurement.

• Terahertz study on the porosity of porous traditional Chinese medicine tablets by effective medium models

  LI Xu, ZHANG Meng-Yuan, ZHAO Wen-Yue, ZUO Jian, ZHU Wei-Feng, LI Zhe, SHI Yu-Lei, ZHANG Cun-Lin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (96) HTML (0) PDF (1006.33 KKB)(129)

  Abstract:

  Generally， the porosity of traditional Chinese medicine is measured by the destructive method of density measurement， but there is a lack of non-destructive quantification methods. As one important non-destructive method， terahertz radiation has been used to non-destructively extract the drugs" time-domain and frequency-domain optical information. For direct compression traditional Chinese medicine tablets， the effective refractive index of various tablets was obtained by different methods of terahertz time-domain signal processing and frequency-domain signal processing. It was found that the effective refractive indices with either signal processing method show a good linear relationship with the porosities of the tablets. The porosity of Puerariae Lobatae Radix tablets was extracted and modeled by linear regression based on four effective medium theory models. The porosity regression model based on the effective refractive index by time-domain signal processing shows better performance on the model interpretation and cross-validation accuracy， with the best model of the Bruggeman model （RPD=11.3325）. It provides support for the process optimization of porous powder preparation of traditional Chinese medicine.

红外材料与器件

• Ultrasensitive and broad-spectrum photodetectors based on InSe/MoTe₂ heterostructure

  XING Yan-Hui, HE Wen-Xin, HAN Zi-Shuo, GUAN Bao-Lu, MA Hai-Xin, MA Xiao-Hui, HAN Jun, SHI Wen-Hua, ZHANG Bao-Shun, LV Wei-Ming, ZENG Zhong-Ming

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (169) HTML (0) PDF (1.24 MKB)(82)

  Abstract:

  The photogating effect based on the vertical structure of a two-dimensional material allows high-sensitivity and broad-spectrum photodetector. A high-sensitivity photodetector based on the vertical heterostructure of indium selenide （InSe）/molybdenum ditelluride （MoTe₂） is reported， which exhibits excellent broad-spectrum detection capability from 365 to 965 nm. The top layer of InSe was used as the grating layer to regulate the channel current， and MoTe₂ was used as the transmission layer. By combining the advantages of the two materials， the photodetector has a fast response time of 21.6 ms and achieves a maximum detectivity of 1.05 × 10¹³ Jones under 365 nm laser irradiation. Under the illumination of 965 nm， the detectivity still achieves the order of 10⁹ Jones. In addition， the InSe/MoTe₂ heterostructure exhibits an external quantum efficiency of 1.03 × 10⁵%， demonstrating strong photoelectric conversion capability.

太赫兹与毫米波技术

• Metalens for polarization-switchable multi-functions multiplexing in multiple channels

  LIU Xiao-Dong, ZHU Yi-Ming

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (50) HTML (0) PDF (1.25 MKB)(127)

  Abstract:

  Metasurface provide a new platform for studying planar and ultrathin optical components. The traditional geometric-phase-based metalens are limited to the polarization locking， which inevitably hinders its function in multiplexing of multiple functions. Herein， an approach based on the geometric phase is proposed to realize polarization decoupling of metalens. This method can be applied to design metalens that enables functionalities of polarization switchable multi-functions（focusing and vortex beam etc...） multiplexing in the longitudinal direction or both the longitudinal and transverse directions. The results provide a new avenue for multifunctional integrated planar components.

红外材料与器件

• Asymmetric tip design for far infrared metamaterial sensor

  LU Xiao-Sen, WU Xu, WEI Xiao-Ke, WANG Jun-Jie, WANG Qi-Liang, JIN Zuan-Ming, PENG Yan

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (62) HTML (0) PDF (1.33 MKB)(157)

  Abstract:

  This study investigates an asymmetric tip design for a far-infrared metamaterial aimed at enhancing the Q factor and detection sensitivity. Employing the conventional double-split square ring resonator as a model， we conducted theoretical simulations to investigate the impact of different tip angles on the electric field distribution， resonance spectrum， and Q factor. The results show that the asymmetric tip increases the surface electric field of the resonator， decreases the full width at half maximum （FWHM） of the resonance peak， and increases the Q factor to over three times that of the conventional split ring. Our findings offer valuable insights for the development of highly sensitive far-infrared metamaterial sensors. Furthermore， we propose a straightforward and practical optimization approach to enhance the Q factor of conventional split ring metamaterials.

太赫兹与毫米波技术

• Dual-band multi-beam reconfigurable terahertz antenna based on graphene frequency selective surface

  JIN Zhao, RONG Yu, QIAO Li-Ping, YU Jing-Dong, WU Fei, TIAN Dou

  DOI:

  Abstract: (51) HTML (0) PDF (1.09 MKB)(287)

  Abstract:

  In this paper， a dual-band graphene-based frequency selective surface （GFSS） is investigated and the operating mechanism of this GFSS is analyzed. By adjusting the bias voltage to control the graphene chemical potential between 0 eV and 0.5 eV， the GFSS can achieve four working states： dual-band passband， high-pass low-impedance， low-pass high-impedance， and band-stop. Based on this GFSS， a hexagonal radome on a broadband omnidirectional monopole antenna is proposed， which can achieve independent 360° six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands. In addition， while increasing the directionality， the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi， respectively. This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.

• The research progress of millimeter-wave power applications

  LU Dun, FU Wen-Jie, MIKHAIL Glyavin, TANG Xiang-Wei, HU Min, LIU Sheng-Gang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (50) HTML (0) PDF (2.82 MKB)(308)

  Abstract:

  In general， all known applications of high-power microwaves directly use energy to interact with matter. In recent years， with the development of powerful millimeter-wave radiation sources， microwave technology has gradually shifted towards the millimeter-wave frequency band. Due to the wavelength of radiation， millimeter waves have several unique characteristics， which allow for both the active development of existing technologies and the creation of new ones that require high power or radiation energy. This article provides an overview of research on the application of millimeter waves to solve problems in physics， material science， biomedicine， and others， including heating and diagnostics of thermonuclear plasma， processing and analysis of materials， biological effects， etc. The main difficulties arising in the implementation of the described tasks are presented， and the future development is also prospected.

• InGaAs/InAlAs InP-based HEMT with the current cutoff frequency 441 GHz

  FENG Rui-Ze, CAO Shu-Rui, FENG Zhi-Yu, ZHOU Fu-Gui, LIU Tong, SU Yong-Bo, JIN Zhi

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (104) HTML (0) PDF (1.15 MKB)(460)

  Abstract:

  In this letter， an In_0.53Ga_0.47As/In_0.52Al_0.48As InP-based HEMT with f_T > 400 GHz was designed and fabricated successfully. A narrow gate recess technology was used to optimize the parasitic resistances. The gate length is 54.4 nm， and the gate width is 2 × 50 μm. The maximum drain current I_DS.max is 957 mA/mm， and the maximum transconductance g_m.max is 1265 mS/mm. The current gain cutoff frequency f_T is as high as 441 GHz and the maximum oscillation frequency f_max reaches 299 GHz， even at a relatively small value of V_DS = 0.7 V. The reported device can be applied to terahertz monolithic integrated amplifiers and other circuits.

• Research on error analysis and instrument parameter configuration of emissivity measurement of multispectral radiometric method based on slow-change assumption

  Luan Yi-Fei, Wang Xiang, Gu Luo, Lin Yue, Yang Qiu-Jie, He Zhi-Ping

  Abstract: (2) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Emissivity, as a key parameter to characterize the radiation properties of an object, and its accurate measurement is of great value for high-temperature target identification, characterization of material modification, and regulation of metal smelting process. The emissivity measurement by multispectral radiation method has become a research hotspot because of its advantages of non-contact and fast measurement speed, and its measurement accuracy is determined by the solution accuracy of the underdetermined system of equations. At present, the research on the solution accuracy of the underdetermined system of equations mainly focuses on the error of the equation solving algorithm, ignoring the measurement error of the spectrometer itself, which leads to the failure of controlling the system error in a reasonable way. In this paper, based on the assumption of retardation with wide application range and high measurement accuracy, the influence of the number of spectral channels and signal-to-noise ratio on the emissivity measurement error under different conditions is simulated, the parameter configurations of the spectrometer under the corresponding conditions are determined, and the effect of emissivity measurement is experimentally verified. The experimental results show that, using the multispectral radiation method based on the slow-change assumption, the number of spectral channels of the spectrometer should be not less than 400 and the signal-to-noise ratio should not be less than 1000 in order to make the blackbody emissivity measurement error less than 1%; for the targets with complex emissivity changes, the spectrometer should have at least 1,000 spectral channels and signal-to-noise ratios of more than 1,200 in order to make the measurement error less than 1%. Comprehensive consideration of the algorithm error and spectrometer parameter matching relationship is the key to rationally control the system error, and more accurate emissivity measurement results can be obtained, which provides a new basis and solution for the application of multispectral radiation method to accurately measure the emissivity, which is of great significance for the accurate identification of high-temperature targets and the application of the related fields.

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• Enhancement of mid-wavelength infrared absorbance by alkane-grafted Ti₃C₂T_x MXene flakes

  赵振宇, Hideaki Kitahara, Zhang Chen-Hao, Masahiko Tani

  Abstract: (2) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  An enhancement of mid-wavelength infrared absorbance is achieved via a cost-effectively chemical method to bend the flakes by grafting two types of alkane octane (C₈H₁₈) and dodecane (C₁₂H₂₆) onto the surface terminals respectively. The chain-length of alkane exceeds the bond-length of surface functionalities Tx (=O,-OH,-F) so as to introduce intra-flake and inter-flake strains into Ti₃C₂T_x MXene. The electronic microscopy (TEM/AFM) shows obvious edge-fold and tensile/compressive deformation of flake. The alkane termination increases the intrinsic absorbance of Ti₃C₂T_x MXene from no more than 50% down to more than 99% in the mid-wavelength infrared region from 2.5 μm to 4.5 μm. Such an absorption enhancement attribute to the reduce of infrared reflectance of Ti₃C₂T_x MXene. The C-H bond skeleton vibration covers the aforementioned region and partially reduce the surface reflectance. Meanwhile, the flake deformation owing to edge-fold and tensile/compression increase the specific surface area so as to increase the absorption as well.

  • 1
• Study on Multi-wavelength Thin Film Thickness Determination Method

  SHI Ce, XIE Mao-Bin, ZHENG Wei-Bo, JI Ruo-Nan, WANG Shao-Wei, LU Wei

  Abstract: (1) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  This work introduces a novel method for measuring thin film thickness, employing a multi-wavelength method that significantly reduces the need for broad-spectrum data. Unlike traditional techniques that require several hundred spectral data points, the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths. This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines. The method effectively reconstructs and fits the visible spectrum (400-800 nm) using a minimal amount of data, while maintaining measurement error within 7.1%. This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.

  • 1
• Liquid Stop based Microfluidic Variable Optical Attenuator Array

  Wan Jing, Yu Tingjie, Chen Jiansong, Zhou Rui, Wan Hongdan

  Abstract: (0) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Variable optical attenuator (VOA) arrays can be widely applied in optical communication and optoelectronic systems, but few VOA arrays are reported. Here a liquid-stop based microfluidic VOA array is proposed. It uses a spiral orbit to achieve different degrees of synchronous energy attenuation of multiple beams, or uses an annular orbit to achieve a same degree of synchronous energy attenuations, where the clear aperture of liquid stop is regulated by the electrowetting-on-dielectric effect. It has a compact structure, small volume, simple operation and low cost. Meanwhile, the attenuation ratio of beams can be flexibly adjusted to achieve the power equalization. The research results indicate that the VOA array has a wide attenuation range (0-100% attenuation) and very small insertion loss (0.26 dB) over general VOA arrays. The response time is 0.1 ms, and it is insensitive to the polarization. It can also act as an optical switch array. The proposed VOA array demonstrates the potential of integration and high performance, and it can provide a cost-effective way for applications.

  • 1
• 75-110 GHz wideband Frequency Tripler Chip Based on Planar Schottky Diode

  CHEN Yan, MENG Fan-Zhong, XUE Hao-Dong, ZHANG Ao, GAO Jianjun

  Abstract: (0) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Based on GaAs planar Schottky diode process, a W band wideband frequency tripler MMIC is designed with a reverse parallel diode pair in this paper. By combining of finite element method and equivalent circuit method, an accurate equivalent circuit model of the planar Schottky diode is built in the frequency range of 10~280GHz. The nonlinear harmonic balance tool is utilized to achieve the optimal frequency tripler design in W band. The measurement results show that the frequency multiplication loss is less than 15dB under 17dBm driving power, efficiency up to 6.7%. The chip size is 0.80mm×0.65mm×0.05mm．

  • 1
• Research of power improvement of a LD directly-pumped mid-infrared pulse solid-state laser

  ZHANG Meng, YANG Xi, GUO Jia-Wei, CAI He, WU Xin-Yang, HAN Ju-Hong, WANG Shun-Yan, WANG You

  Abstract: (2) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  A LD directly-pumped solid-state laser is considered to be one of the most promising mid-infrared light sources because of its simple principle, small size, and compact structure for the generation of mid-infrared (MIR) lasers in the 3~5 μm band. However, the quantum defect of LD directly-pumped MIR solid-state lasers will be much larger than that of ordinary near-infrared LD pumped solid-state lasers, which may lead to thermal damage and limit their development. In order to solve this problem, the methods of reducing the specific surface area of the crystal and improving the thermal energy released by the crystal structure are discussed, and the optimal length of the laser crystal is determined. The cooling structures of barium yttrium fluoride laser crystals (Ho3+^:BY2F8) of different lengths were studied by thermal simulation using COMSOL software. The experimental results show that the output power can be increased and the thermal stress in the laser crystal can be alleviated by using the laser crystal whose length is slightly shorter than that of the cooler. The final experiment shows that when the pump repetition rate is 15 Hz and the pulse width is 90 μs, the output wavelength of the laser is about 3.9 μm and the single pulse energy is 7.28 mJ, which is about 3 times that of the crystal-I. Such results should be another breakthrough of our team since the first directly-pumped solid-state MIR laser was realized more than a year ago. It might pave the way for the construction of a feasible MIR laser in the near future.

  • 1
• Deep Plug-and-Play Self-Supervised Neural Networks for Spectral Snapshot Compressive Imaging

  Zhang Xing-Yu, Zhu Shou-Zheng, Zhou Tian-Shu, Qi Hong-Xing, Wang Jian-Yu, Li Chun-Lai, Liu Shi-Jie

  Abstract: (11) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The coded aperture snapshot spectral imaging system, based on compressed sensing theory, functions as an capable of efficiently acquiring compressed two-dimensional spectral data. This data is subsequently decoded into three-dimensional spectral data through a deep neural network. However, training the deep neural network necessitates a substantial amount of clean data, which is often challenging to obtain. To address the issue of insufficient training data for deep neural network, a self-supervised hyperspectral denoising neural network is proposed, leveraging the concept of neighborhood sampling. This network is integrated into the deep plug-and-play framework, enabling self-supervised spectral reconstruction. The study also examines the impact of different noise degradation models on the final reconstruction quality. Experimental results demonstrate that compared with supervised learning method, the self-supervised learning method enhances the average peak signal-to-noise ratio by 1.18dB and improves the structural similarity is improved by 0.009. Additionally, it achieves superior visual reconstruction outcomes without relying on clean data as labels.

  • 1
• Study on photoelectric performance of ultra-small pixel pitch micro-mesa InGaAs detector

  TIAN Yu, YU Chun-Lei, LI Xue, SHAO Xiu-Mei, LI Tao, YANG Bo, YU Xiao-Yuan, CAO Jia-Shen, GONG Hai-Mei

  Abstract: (16) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The pursuit of ultra-small pixel pitch InGaAs detectors necessitates a meticulous approach to addressing challenges associated with crosstalk reduction and dark current minimization. By developing the fabrication process technology of micro-mesa InGaAs detector, a test structure featuring a micro-mesa InGaAs photosensitive chip with 10μm and 5μm pixel pitch was successfully prepared. Subsequently, a comprehensive investigation was conducted to analyze the impact of the micro-mesa structure on crosstalk and dark current characteristics of the InGaAs detector. The obtained results revealed the efficacy of the micro-mesa structure in effectively suppressing crosstalk between adjacent pixels when the isolation trench etches into the absorption layer. However, a noteworthy challenge emerged as the fabrication processes induced material damage, leading to a considerable increase in recombination current and ohmic leakage current. This adverse effect, in turn, manifested as a dark current escalation by more than one order of magnitude. The significance of these findings lies in offering a novel perspective for the manufacturing of ultra-small pixel pitch InGaAs focal plane detectors.

  • 1
• GaSb-based tensile-strained Ge quantum dots for mid-infrared lasers

  Cao You-Xiang, Dai Jin-Meng, Zhang Li-Yao

  Abstract: (22) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Ge can be converted into direct bandgap material under tensile strain. Pyramid-shaped Ge quantum dots (QDs) on GaSb system is proposed. The strain distribution and band structures are investigated with different QD sizes. Flat Ge QDs are desirable for indirect to direct band gap conversion. Light emission from 1.8 μm to 5.8 μm can be achieved from Ge/GaSb QDs with the width ranges from 4 to 14 nm and the height ranges from 1 to 5 nm. A 3.1 μm laser with Ge/GaSb QDs with height of 3 nm and width of 12 nm is designed and the device performance is simulated at room temperature. The QD size fluctuations are also considered. Under the root mean square of QD size fluctuation of 0.22, the calculated optimal optical confinement factor, thickness of the waveguide, surface density of QDs are 0.013, 0.366 μm and 3.8×1010 ^cm-2^, respectively, while the minimum threshold current density is 28.98 A/cm2^. This work provides a feasible way for the fabrication of mid-infrared lasers.

  • 1
• A HgTe/ZnO Quantum Dots Vertically Stacked Heterojunction Low dark current Photodetector

  HUANG Xin-Ning, JIANG Teng-Teng, DI Yun-Xiang, XIE Mao-Bin, GUO Tian-Le, LIU Jing-Jing, WU Bin-Min, SHI Jing-Mei, Qin Qiang, DENG Gong-Rong, CHEN Yan, LIN Tie, SHEN Hong, MENG Xiang-jian, WANG Xu-Dong, CHU Jun-Hao, GE Jun, WANG Jian-lu

  Abstract: (65) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Colloidal quantum dots (CQDs) are affected by the quantum confinement effect, which makes their bandgap tunable. This characteristic allows these materials to cover a broader infrared spectrum, providing a cost-effective alternative to traditional infrared detector technology. Recently, thanks to the solution processing properties of quantum dots and their ability to integrate with silicon-based readout circuits on a single chip, infrared detectors based on HgTe CQDs have shown great application prospects. However, facing the challenges of vertically stacked photovoltaic devices, such as barrier layer matching and film non-uniformity, most devices integrated with readout circuits still use a planar structure, which limits the efficiency of light absorption and the effective separation and collection of photo-generated carriers. Here, by synthesizing high-quality HgTe CQDs and precisely controlling the interface quality, we have successfully fabricated a photovoltaic detector based on HgTe and ZnO QDs. At a working temperature of 80 K, this detector achieved a low dark current of 5.23×10-9 ^A cm-², a high rectification ratio, and satisfactory detection sensitivity. This work paves a new way for the vertical integration of HgTe CQDs on silicon-based readout circuits, demonstrating their great potential in the field of high-performance infrared detection.

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• Current research status of terahertz biomedical applications

  GUO Yuan-Sen, CHEN Li-Gang, YAN Shi-Han, FU Ying, QIU Fu-Cheng, YANG Zhong-Bo, ZHANG Ming-Kun, TANG Ming-Jie, WANG Hua-Bin

  Abstract: (72) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Terahertz (THz) technology is undergoing a rapid development in biomedical applications. Researchers have made a series of important achievements in the study of biological samples on various levels such as biomolecules, cells, tissues, and individual organisms, which provide new insights and innovative approaches for biological research and biomedical diagnosis. In this review, the progress of applying THz technology in biomedical studies has been summarized, including three key aspects, namely, spectroscopic detection, imaging, and biological effects. The challenges encountered in THz biomedical applications have been discussed, and the future development directions have also been envisioned.

  • 1
• Angular-tunable on-chip coding metasurface enabled by phase-change material with immersion liquid

  LI Xue-Nan, ZHAO Zeng-Yue, YU Fei-Long, CHEN Jin, LI Guan-Hai, LI Zhi-Feng, CHEN Xiao-Shuang

  Abstract: (16) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves. Coupled with phase-change materials, they facilitate the creation of versatile metadevices, showcasing various tunable functions based on the transition between amorphous and crystalline states. However, the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices. Here, this paper introduce a novel approach—a multi-functional metadevice achieved through the two-level control of the encoding phase-change metaatoms. Utilizing the phase-change material Ge2Sb2Se4Te1 (GSST) and high refractive-index liquid diiodomethane (CH2I2), this paper showcase precise control over electromagnetic wave manipulation. The GSST state governs the tunable function, switching it ON and OFF, while the presence of liquid in the hole dictates the deflection angle when the tunable function is active. Importantly, our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum. The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice, enabling dynamic switching of encoding bit levels. This two-level tunable metadevice, rooted in phase-change materials, presents a promising avenue for the dynamic control of functions.

  • 1
• Influence of crystal temperature on femtosecond laser induced ferroelectric domain inversion process

  XU Tian-xiang, WANG Sen, LIN Jin-yang, ZHAO Ru-wei, XU Tie-feng, SHENG Yan

  Abstract: (26) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The near-infrared femtosecond laser induced ferroelectric domain inversion in an important method in 3D nonlinear photonic crystal fabrication. Using structures produced by this technique, a series of attractive results have been achieved in optical frequency conversion and nonlinear wavefront shaping. At present, the reported laser induced domain inversion were all implemented at room temperature. For ferroelectric crystals, it would reach the Curie point during heating, and many characterizations such as coercive field which relate to domain inversion may change seriously. However, the effect of crystal temperature on femtosecond laser induced domain inversion is undefined. In this work, the strontium barium niobate (Sr_xBa_1-xNbO₃) ferroelectric crystal with the Curie point of about 70-80℃ depends on component proportion of Sr and Ba was used for domain inversion. Direct near-infrared femtosecond laser writing was implemented at the temperature of 25-65℃. The domain inversion condition was judged based on the second-harmonic pattern in far field. The variation tendency of threshold laser power for domain inversion depends on temperature was tested and possible reason was predicted.

  • 1
• Ion Implantation Process and Lattice Damage Mechanism of Boron Doped Crystalline Germanium

  HABIBA Um E, CHEN Tian-Ye, LIU Chi-Xian, DOU Wei, LIU Xiao-Yan, LING Jing-Wei, PAN Chang-Yi, WANG Peng, DENG Hui-Yong, SHEN Hong, DAI Ning

  Abstract: (89) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The response wavelength of the boron doped germanium (Ge:B) blocked-impurity-band (BIB) structured infrared detector can reach 200μm, which is the most important very long wavelength infrared astronomical detector. The ion implantation method greatly simplifies the fabrication process of the device, but it is easy to cause lattice damage, introduce crystalline defects, and lead to the increase of the dark current of detectors. Herein, the boron-doped germanium ion implantation process was studied, and the involved lattice damage mechanism was discussed. Experimental conditions involved using 80 keV energy for boron ion implantation, with doses ranging from 1×10^13 to 1×10^15cm^-2. After implantation, thermal annealing at 450°C was implemented to optimize dopant activation and mitigate the effects of ion implantation. Various sophisticated characterization techniques, including X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS) were used to clarify lattice damage. At lower doses, no notable structural alterations were observed. However, as the dosage increased, specific micro distortions became apparent, which could be attributed to point defects and residual strain. The created lattice damage was recovered by thermal treatment, but an irreversible strain induced by implantation still existed at the high doses.

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• 300GHz OFDM Electronic Terahertz Wireless Transmission based on PS and DFT-S

  JIANG Lu-Han, YU Jian-Jun

  Abstract: (18) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  To meet the high-speed and high-capacity demands of communication, a 300GHz electronic terahertz wireless transmission system is proposed, which incorporates Probability Shaping (PS), Discrete Multi-tone Modulation (DMT) and DFT-Spread (DFT-S) techniques. PS increases the Euclidean distance between constellation points, thereby enhancing the receiver sensitivity. In the system at most 55% bit error rate is decreased, enabling to extend transmission range. DFT-S technique reduces 1.68 dB peak-to-average power ratio of Orthogonal Frequency Division Multiplexing (OFDM) signals in the system, thus improving their resistance to nonlinear effects. In the 300GHz terahertz wireless transmission system, 12GBaud PS-16QAM OFDM-DMT signals and 10GBaud PS-64QAM DFT-S-OFDM-DMT signals were successfully implemented in 1m wireless transmission. Finally, the performance advantages of these digital signal processing techniques were compared.

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• Lightweight Remote Sensing Scene Classification Based on Knowledge Distillation

  ZHANG Chong-Yang, WANG Bin

  Abstract: (25) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Remote sensing image scene classification aims to automatically assign a semantic label to each remote sensing image according to its content, and has become one of the hot topics in the field of remote sensing image processing. Methods based on convolutional neural networks (CNNs) and methods based on self-attention mechanism are two mainstream methods in remote sensing image scene classification. However, the former is less effective in exploring long-range contextual information, and the latter has limitations in learning local information and has a large number of parameters and calculations. In order to address these issues, a lightweight method based on knowledge distillation is proposed to solve the problem of scene classification for remote sensing images. The proposed method uses Swin Transformer and lightweight CNNs as the teacher model and the student models, respectively, and integrates the advantages of the two kinds of models by means of knowledge distillation. Furthermore, a novel distillation loss function is proposed to enable the student models to focus on both inter- and intra-class potential information of remote sensing images simultaneously. The experimental results on two large-scale remote sensing image datasets demonstrate that the proposed method not only achieves high classification accuracy compared to existing methods but also has a significantly reduced number of parameters and calculations.

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• Cavity-type Metasurface Uncooled Infrared Detector

  YANG jun, YANG Chun-li, FANG Hui, YUAN Jun, YAN Shan-ru, LI Hua-ying, LI Bingzhe

  Abstract: (14) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  As the cell size of uncooled infrared (IR) detectors progressively shrinks, it becomes increasingly important to increase detector absorption. here, an IMIAM (Insulator-Metal-Insulator-Air-Metal) cavity type metasurface uncooled IR detector structure is proposed, which effectively improves the uniformity of the photosensitive layer while enhancing the absorption of the detector. Utilizing systematic simulation and optimization, it has achieved almost perfect absorption in the Long Wavelength Infrared range (8~14um), meanwhile, it also shows excellent absorption performance in Mid Wavelength Infrared band. In this paper, the reliability of the structure is also verified by the process. this research may provide alternatives for optimizing conventional uncooled IR detectors.

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• Long Wavelength Infrared Metalens Fabricated by Photolithography

  LI Yun-Peng, LUO Jia-Cheng, JI Ruo-Nan, XIE Mao-Bin, CUI Wen-Nan, WANG Shao-Wei, LIU Feng, LU Wei

  Abstract: (64) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Metasurfaces in the long wave infrared (LWIR) spectrum hold great potential for applications in thermal imaging, atmospheric remote sensing, and target identification, among others. In this study, we designed and experimentally demonstrated a 4 mm size, all-silicon metasurface metalens with large depth of focus operational across a broadband range from 9 μm to 11.5 μm. The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region, thus paving the way for practical LWIR applications of metalens technology.

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• The influence of V/III ratio on electron mobility of the InAsxSb1-x layers grown on GaAs substrate by molecular beam epitaxy

  zhang jing, Yang zhi, zheng liming, zhu xiaojuan, wang ping, yang lin

  Abstract: (12) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  This paper discusses the influence of Sb/In ratio on the transport properties and crystal quality of the 200 nm InAsxSb1-x thin film. The Sb content of InAsxSb1-x thin film in all sample was verified by HRXRD of the symmetrical 004 reflections and asymmetrical 115 reflections. The calculation results show that the Sb component is 0.6 in the InAsxSb1-x thin film grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3, which has the highest electron mobility (28560 cm2/V·s) at 300 K. At the same time, the influence of V/III ratio on the transport properties and crystal quality of Al0.2In0.8Sb/InAsxSb1-x quantum well heterostructures also has been investigated. As a result, the Al0.2In0.8Sb/InAs0.4Sb0.6 quantum well heterostructure with a channel thickness of 30 nm grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3 has a maximum electron mobility of 28300 cm2/V·s and a minimum RMS roughness of 0.68 nm. Through optimizing the growth conditions, our samples have higher electron mobility and smoother surface morphology.

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• Study of Silicon Nitride Waveguide-Based Ultra-Wideband On-Chip Light Source for OCT Applications

  HUI Zhan-Qiang, LI Jia-ying, LI Tian-Tian, HAN Dong-Dong, GONG Jia-Min

  Abstract: (49) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Optical coherence tomography (OCT) technology has the advantages of non-invasive, high-resolution, and real-time imaging, which is widely used in various fields such as biomedicine, material science and infrared sensing. In this paper, a ridge suspended optical waveguide based on silicon nitride (Si₃N₄) is proposed. The structural parameters of the designed waveguide were optimized by using finite difference time domain (FDTD) method. The characteristics of the supercontinuum spectrum generated in the optimized waveguide were investigated The simulation results show that for the optimized optical waveguide structure with ridge width of 750nm, ridge height of 700nm, plate thickness of 200nm, and upper layer height of 150nm, when a pump light with wavelength of 1.3μm, peak power of 2kW and pulse width of 50fs was injected into the waveguide, a broadband supercontinuum spectrum with wavelength covering the visible to the mid-infrared region (703~4014nm) can be generated. This work plays an important role in promoting the application of on-chip integrated broadband light source in biomedical imaging and related fields.

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• High-precision spot centroid positioning of high-frame-rate short-wave infrared images for satellite laser communication

  FU Peng, HE Dao-Gang, LIU Jun, WANG Yue-Ming

  Abstract: (46) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction. In satellite laser communication systems, the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation. However, there are strong non-uniformity and blind pixels in the short-wave infrared image, which makes the image distorted and leads to the decrease of spot centroid positioning accuracy. Therefore, the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance. A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two, further model-based localization error simulations are performed, and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector. The experimental results show that the non-uniformity of the corrected image is reduced from 7% to 0.6%, the blind pixels rejection rate reaches 100%, the frame rate can be up to 2000 Hz, and the spot centroid localization accuracy is as high as 0.1 pixel point, which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images. The payload has now passed the spaceflight environment screening experiment, and will subsequently be put into use as the core payload of satellite laser communication.

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• The different characteristics of front and backside configurations of photoreflectance based on grating spectrometer

  Zhan Jia, ZHA Fang-Xing, GU Yi

  Abstract: (16) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Photoreflectance (PR) has been widely used for the characterization of various semiconductors as well as their surface and interface properties due to its non-destructive and high sensitivity virtues. From the viewpoint of the employment of monochromator, the experimental setup may be classified into front and backside (or dark and bright) configurations, which were applied to characterize the heterostructure of InP/In0.52Ga0.48As/InP grown by molecular beam epitaxy. It reveals that the front configuration well separates the luminescence from the modulation signal while the backside configuration benefits the extraction of weak modulation signals with the employment of high excitation power. Based on the backside configuration, we also observed a below band-gap excitation phenomenon, i.e. that the modulation signal of InP exhibits under the excitation of energetically low modulation light (1064 nm laser). The result demonstrates that the backside configuration may be employed as a contactless electro-modulation technique for the characterization of wide band gap semiconductor heterostructures.

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• Dual zinc diffusion behaviors in InGaAs/InP single photon avalanche photodiodes

  LIU Mao-Fan, YU Chun-Lei, MA Ying-Jie, YU Yi-Zhen, YANG Bo, TIAN Yu, BAO Peng-Fei, CAO Jia-Sheng, LIU Yi, LI Xue

  Abstract: (49) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Theoretical and experimental investigations on the dual-diffusion behaviors of zinc atoms in InGaAs/InP single photon avalanche photodiode (SPAD) are performed. A formula of Xj=k(t-t0)^0.5+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice diffusion depths based on a two-dimensional (2D) model. The 2D impurity morphologies and the one dimensional impurity profiles for the dual-diffused region are characterized by using the scanning electron microscopy and the secondary ion mass spectrometry as a function of the diffusion depth respectively. InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated which show breakdown behaviors well consistent with the simulated results under the same junction geometries. Dark count rate measurements are carried out as well. These results demonstrate an effective prediction route for accurately control of the dual-diffused zinc junction geometry in InP based planar device processing.

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• The Effect of Doping on the Optical and Physicochemical Properties of YbF3 and Its Application in Infrared Coatings

  MA Qiu-Jing, DUAN Wei-Bo, YU Tian-Yan, LI Da-Qi, YU De-Ming, LIU Bao-Jian, ZHUANG Qiu-Hui, LIU Ding-Quan

  Abstract: (84) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The effects of calcium fluoride (CaF2) doping on the optical and physical and chemical properties of Ytterbium fluoride (YbF3) materials were studied. Pure YbF3 thin films and YbF3 thin films doped with different proportions of CaF2 were deposited by electron beam and thermal evaporation, respectively. The characteristics of single layer were measured by spectrometer, stress measurement system, X-ray Diffraction (XRD), Atomic Force Microscope (AFM) and other measuring devices. The optical constants were fitted by the classical Lorentz oscillator model. The results show that the single-layer film with better optical and physical and chemical properties is obtained by electron beam deposition, in the condition of 1% CaF2 doping. A long-wave infrared anti-reflection multi-layer sample was designed and fabricated and its spectrum and reliability test were carried out. The results show that its transmittance in the long-wave infrared region is as high as 99%, and the reliability meets the requirements of space application.

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• Research on the Key Technologies and Applications of Aerospace Metaverse

  WANG Zhong, SUN Sheng-Li, CHEN Rui, MA Yi-Jun, XU Wen-Jun, ZHANG Ya-Feng

  Abstract: (26) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Through sufficient investigation and summary, the development trend and representative work of Metaverse and related technologies in the aerospace field since the 1960s have been sorted out, and it is pointed out that multi-satellite networking, digitalization and virtualization will become important development trends of aerospace science and technology. Hence, a new concept called “Aerospace Metaverse” has been proposed. Based on this concept, the fundamentals of mathematics and physics have been analyzed. Necessry technologies to build Aerospace Metaverse such as digital twins of aerospace and all-optical perception have been proposed, and their implementation approaches are elaborated. Furthermore, combining with the vigorous development of aerospace technology, scenarios that can be first put into use have been predicted. Several existing difficulties in building Aerospace Metaverse and corresponding solutions have been proposed, providing new ideas for the development of aerospace technology.

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• Imaging simulation and analysis of attitude jitter effect on topographic mapping for lunar orbiter stereo optical cameras

  CHEN Chen, TONG Xiao-Hua, LIU Shi-Jie, YE Zhen, WU Hao, ZHANG Han

  Abstract: (47) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevitably affected by the obiter attitude jitter. Therefore, it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching. In this work, an imaging simulation method considering the attitude jitter is presented. The impact analysis of different attitude jitter on terrain undulation is conducted by simulating jitter at three attitude angles, respectively. The proposed simulation method is based on the rigorous sensor model, using the lunar digital elevation model (DEM) and orthoimage as reference data. The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter. Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit. Experimental analyses were conducted by the DEM with the simulated stereo image. The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping. The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through DEM comparison.

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• 1.2 Experimental study on laser ranging of space target for m quantum communication telescope

  Yang Yu, LONG Ming-Liang, ZHANG Hai-Feng, ZHANG Xiao-Xiang, HUANG Xing-Min, DING Jie, LI Pu, DENG Hua-Rong, ZHANG Zhong-Ping

  Abstract: (49) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  High-precision space debris measurement can provide more accurate real-time information of debris targets and enhance the effectiveness of satellite avoidance and early warning of space debris. The satellite laser ranging (SLR) and space debris laser ranging (DLR) experiments were carried out by using picosecond laser with pulse energy of 1.2 mJ and repetition frequency of 1 kHz. The atmospheric propagation characteristics of picosecond laser were studied and analyzed. The cooperative satellites measured distances from 500 km to 36000 km with ranging accuracy better than 2 cm. The maximum distance of space debris target measurement is 1620.5 km, the radar cross section (RCS) is 2.41 m2, and the ranging accuracy reaches 10.64 cm. It is realized that a single laser system can carry out centimeter-level precision ranging of cooperative targets and space debris observation. This is the first time in the world to use high repetition frequency and low power laser ranging system to achieve high precision measurement of space debris targets, reflecting the advantages of picosecond laser and high altitude large aperture telescope measurement, providing an effective way for space debris laser ranging system site selection and space debris monitoring capability enhancement.

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• Spatial and temporal distribution of extinction and microphysical properties in the upper haze of Venus

  LI Yi-Qi, SUN Xiao-Bing, HUANG Hong-Lian, LIU Xiao, TI Ru-Fang, ZHENG Xiao-Bing, YU Hai-Xiao, WEI Yi-Chen, WANG Yu-Xuan, WANG Yu-Yao

  Abstract: (31) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Variations of extinction and microphysical properties in the upper haze of Venus will affect the chemistry and radiative balance of the Venus atmosphere. To study their spatial and temporal distribution, solar occultation data from Venus Express SPICAV SOIR instruments between 2006 and 2013 were analyzed. The absorption effects of the Venus' middle and upper atmosphere were first removed using MODTRAN modeling. The extinction profiles of the upper haze between 67～92 km were then retrieved using the onion-peeling method. The results show that: 1) The extinction coefficient of the upper haze generally decreased with increasing altitude. Large variations existed between different regions. The extinction at low latitudes increased sharply early in the mission and the average extinction coefficient of haze changes slightly between day and night. The vertical optical depth of the haze layer was on the order of 10-2. 2) The number density of the upper haze decreased with increasing altitude. From south to north pole, the number density first increased and then decreased. 3) Cloud top altitude is higher in low-latitude regions at 82.7 ± 5.8 km, whereas in polar regions cloud top altitude is lower with the the northern polar region at 73.3 ± 2.4 km, and the southern polar region at 79.5 ± 3.5 km. The average scale height of the upper haze layer in the northern polar region is 4.0 ± 0.9 km.

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• A novel self-alignment method for high precision silicon diffraction microlens arrays preparation and its integration with infrared focal plane arrays

  HOU Zhi-Jin, Chen Yan, Wang Xu-Dong, Wang Jian-Lu, Chu Jun-Hao

  Abstract: (49) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Silicon (Si) diffraction microlens arrays are usually used to integrating with infrared focal plane arrays (IRFPAs) to improve their performance. The errors of lithography are unavoidable in the process of the Si diffraction microlens arrays preparation in the conventional engraving method. It has a serious impact on its performance and subsequent applications. In response to the problem of errors of Si diffraction microlens arrays in the conventional method, a novel self-alignment method for high precision Si diffraction microlens arrays preparation is proposed. The accuracy of the Si diffractive microlens arrays preparation is determined by the accuracy of the first lithography mask in the novel self-alignment method. In the subsequent etching, the etched area will be protected by the mask layer and the sacrifice layer or the protective layer. The unprotection area is carved to effectively block the non-etching areas, accurately etch the etching area required, and solve the problem of errors. The high precision Si diffraction microlens arrays is obtained by the novel self-alignment method and the diffraction efficiency could reach 92.6 %. After integrating with IRFPAs, the average blackbody responsity increased by 8.3 %, and the average blackbody detectivity increased by 10.3 %. It indicates that the Si diffraction microlens arrays can improve the filling factor and reduce crosstalk of IRFPAs through convergence, thereby improving the performance of the IRFPAs. The results are of great reference significance for improving their performance through optimizing the preparation level of micro nano devices.

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Volume 43,2024 Issue 2

• LOW-TEMPERATURE RAMAN SCATTERING SPECTRA AND ELECTRICAL PROPERTIES OF Cd_1-xZn_xTe(x=0.04) OF DIFFERENT SURFACE TREATMENTS

  PEI Hui-Yuan

  2001,20(3):184-188, DOI:

  Abstract: (1543) HTML (139) PDF (262.82 KKB)(51368)

  Abstract:

  测量了几种不同处理的Cd1-xZnxTe(x=0.04)表面的傅里叶变换拉曼散射光谱和电流－电压（I－V）特性。通过分析拉曼光谱反Stokes分量，并与表面I－V特性进行比较，结果表明与表面处理相联系的晶格声子的行为反映了表面完整性的变化，Te沉淀是影响表面质量的关键因素，并对有关表面处理方法的实际应用进行了讨论。

• TWO-FREQUENCY SCATTERING CROSS SECTION AND PULSE BROADINGENING FOR THE FRACTAL SEA SURFACE WITH PULSE BEAM INCIDENCE

  GUO Li Xin 1) KIM Che Young 2)

  2003,22(2):132-136, DOI:

  Abstract: (922) HTML (132) PDF (396.69 KKB)(30720)

  Abstract:

  根据粗糙面基尔霍夫小斜率近似研究了脉冲波入射时实际海谱分布的一维分形海面的电磁散射。分析了毫米波入射时不同分维、入射角和入射中心频率下双频散射截面的散射角分布。结果表明分形海面的双频散射截面在镜反射方向有最大的相关带宽，随着海面分维的减小、入射中心频率和入射角的增加，该相关带宽是增大的。对于入射功率为δ函数时的散射波功率是一个具有一定脉冲展宽的散射脉冲，且脉冲展宽与相关带宽成反比关系。

• SEGMENTATION BASED ON MUMFORD-SHAH MODEL COMBINED WITH NARROW BAND

  Abstract

  2002,21(3):161-166, DOI:

  Abstract: (2334) HTML (123) PDF (392.26 KKB)(21123)

  Abstract:

  A segmentation model that combines the Mumford Shah(M S) model and narrow band scheme of level set was presented. The disadvantage of Mumford Shah model is computationally time consuming. In each step of its iteration, the data of whole image have to be renewed, which is unbearable for segmentation of large image or 3D image. Therefore, a fast segmentation model was introduce, which combines the M S model and narrow band scheme by a new initialization method. The new initialization method is based on fast marching method, and the computing time decreases to O(N) . In each step of iteration, the new segmentation model only deals with the data in a narrow band instead of the whole image. The experiments show that the two models can obtain almost the same segmentation result, but the computing time of new narrow band M S model is much less than that of M S model.

• OPTICAL PROPERTIES OF PbTiO3 THIN FILMS PREPARED BY A MODIFIED SOL-GEL PROCESSING

  HU Zhi Gao WANG Gen Shui HUANG Zhi Ming CHU Jun Hao

  2002,21(3):175-179, DOI:

  Abstract: (7658) HTML (465) PDF (411.06 KKB)(21059)

  Abstract:

  采用溶胶－凝胶法在石英玻璃衬底上制备出均匀透明的无定形PbTiO3薄膜，并对其 光学性质进行了详细的研究，发现其折射率的波形符合经典的Cauchy函数。由半导体理论计算得到无定形的PbTiO3薄膜的光学禁带宽度为3．84eV.FTIR透射光 谱研究表明无定形PbTiO3薄膜在中红外波段没有吸收峰出现，对于在550℃下 快速热退火得到的PbTiO3薄膜，通过远红外反射光谱测量，观察到了6个约外活性声子膜。

Infrared Spectroscopy and Spectral Analysis

• DETECTING THE MELAMINE OF PURE MILK BY NEAR INFRARED SPECTRA

  XU Yun, WANG Yi-Ming, WU Jing-Zhu, ZHANG Xiao-Chao

  2010,29(1):53-56, DOI:

  Abstract: (10484) HTML (415) PDF (221.64 KKB)(14849)

  Abstract:

  NIRS was used in rapid qualitative and quantitative detection for melamine of pure milk in this paper. Experiment was conducted by preparing two groups pure milk samples which melamine content is different for qualitative analysis and quantitative analysis. By combining NIRS technology with the cluster analysis method, A effective classification can be made on the two kinds of milk samples with and without melamine; To achieve this, spectrum pretreatment and wave length choice methods were employed before model optimization. The results showed that NIR models of predicting melamine content in pure milk has good stability and predictive ability.This paper suggested that NIR could be used as a quick, green and convenient method for predicting melamine content of dairy.

• INFRARED OBJECT TRACKING BASED ON PARTICLE FILTERS

  CHENG Jian, ZHOU Yue, CAI Nian, YANG Jie

  2006,25(2):113-117, DOI:

  Abstract: (7258) HTML (402) PDF (271.63 KKB)(14189)

  Abstract:

  The particle filter is an effective technique for the state estimation in non-linear and non-Gaussian dynamic systems. A novel method for infrared object robust tracking based on particle filters was proposed. Under the theory framework of particle filters, the posterior distribution of the infrared object is approximated by a set of weighted samples, while infrared object tracking is implemented by the Bayesian propagation of the sample set. The state transition model is chosen as the simple second-order auto-regressive model, and the system noise variance is adaptively determined in infrared object tracking. Infrared objects are represented by the intensity distribution, which is defined by the kernel-based density estimation. By calculating the Bhattacharyya distance between the object reference distribution and the object sample distribution, the observation probability model is constructed. Experimental results show that our method is effective and steady.

Image Processing and Software Simulation

• INFRARED TARGET EXTRACTION ALGORITHM BY USING PARTICLE SWARM OPTIMIZATION PARTICLE FILTER

  ZHOU Yue, MAO Xiao-Nan

  2010,29(1):63-68, DOI:

  Abstract: (11301) HTML (439) PDF (750.21 KKB)(11971)

  Abstract:

  A novel infrared target extraction algorithm based on particle swarm optimization particle filter(PSOPF) was proposed. The problem of infrared target extraction was analyzed and solved in the view of state estimation. In the framework of particle filter, the threshold state space on the gray-variance weighted information entropy and the grey value of each pixel was based on extraction results evaluation function, which integrated grey, entropy, gradient and spatial distribution of pixels. Finally, the weighted average of all the particles was used as target extraction threshold. The experiment results prove that the proposed algorithm is effective and robust.

• IMAGE SEGMENTATION BY SPECTRAL CLUSTERING ALGORITHM WITH SPATIAL COHERENCE CONSTRAINTS

  JIA Jian-Hua, JIAO Li-Cheng

  2010,29(1):69-74, DOI:

  Abstract: (11272) HTML (387) PDF (808.83 KKB)(11704)

  Abstract:

  Image segmentation is one of the difficult problems in computer vision research. Recently spectral clustering has a wide application in pattern recognition and image segmentation. Compared with traditional clustering methods, it can cluster samples in any form feature space and has a global optimal solution. Originating from the equivalence between the spectral clustering and weighted kernel K-means, the authors proposed a spectral clustering algorithm with spatial constraints based on the spatially coherent property of images, also named continuous property. The spatially coherent property means that pixels in the neighbor region should share the same label assignment with the centre one with a high probability. The algorithm adds a term of spatial constraints to the objective function of weighted kernel K-means and makes the minimization of the objective function be equivalent to the spectral clustering through approximation. Experimental results show that our proposed algorithm outperforms the traditional spectral clustering in image segmentation.

• HYPERSPECTRAL REMOTE SENSING IMAGE CLASSIFICATION BASED ON SUPPORT VECTOR MACHINE

  TAN Kun, DU Pei-Jun

  2008,27(2):123-128, DOI:

  Abstract: (2885) HTML (936) PDF (735.00 KKB)(11496)

  Abstract:

  多数传统分类算法应用于高光谱分类都存在运算速度慢、精度比较低和难以收敛等问题.本文从支持向量机基本理论出发建立了一个基于支持向量机的高光谱分类器,并用国产OMIS传感器获得的北京中关村地区高光谱遥感数据进行试验,分析比较了各种SVM核函数进行高光谱分类的精度,以及网格搜寻的方法来确定C和愕闹?结果表明SVM进行高光谱分类时候径向基核函数的分类精度最高,是分类的首选.并且与神经网络径向基分类算法以及常用的最小距离分类算法进行比较,分类的精度远远高于SVM分类算法进行分类的结果.SVM方法在高光谱遥感分类领域能得到广泛的应用.

• OPTICAL SPECTRA OF LOW-DIMENSIONAL SEMICONDUCTORS

  FuY ChiragwandiZ GoethbergP WillanderM

  2003,22(6):401-405, DOI:

  Abstract: (911) HTML (128) PDF (483.11 KKB)(11377)

  Abstract:

  We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion.

• EFFECTS OF APODIZATION FUNCTIONS OF IMAGING FOURIER TRANSFORM SPECTROMETER ON RECONSTRUCTED SPECTRUM

  ZHANG Wen-Juan, ZHANG Bing, ZHANG Xi, GAO Lian-Ru, ZHANG Wei

  2008,27(3):227-233, DOI:

  Abstract: (11695) HTML (435) PDF (1.12 MKB)(10702)

  Abstract:

  随着搭载干涉成像光谱仪HJY20-1-A的我国环境与减灾遥感卫星HJ-1A即将发射,我国干涉光谱成像研究也从实验室开始走向实用化.在干涉光谱成像过程中,切趾函数处理是干涉成像光谱仪光谱复原过程中的一个重要环节,对复原光谱的精度有着极其重要的影响.根据HJY20-1-A的参数设置,文中首先模拟了24种典型地物对应于HJY20-1-A和其它最大光程差设置的干涉成像光谱仪数据,在不同切趾函数作用下的复原光谱,结果表明Hanning函数是其中最有效、最为稳定的切趾函数,同时发现切趾函数的应用虽然可以提高复原光谱的精度,但与真实光谱仍存在一定差距,尤其对应HJY20-1-A,复原光谱的精度更加有限.在以上分析基础上,提出了基于仪器线型函数标准化的光谱复原改进算法,实验结果证实了该方法可以显著提高复原光谱精度,尤其适用于最大光程差较小的空间调制型干涉成像光谱仪.最后,就HJY20-1-A复原光谱对3种典型植被指数求解,进一步证明了该方法的有效性.

• IMAGE RETRIEVAL BASED ON IMAGE ENTROPY AND SPATIAL DISTRIBUTION ENTROPY

  SUN Jun-Ding, DING Zhen-Guo, ZHOU Li-Hua

  2005,24(2):135-139, DOI:

  Abstract: (1333) HTML (99) PDF (380.01 KKB)(10698)

  Abstract:

  A new image retrieval algorithm based on image entropy and spatial distribution entropy was presented. At first a more robust method, which can remove the influence of the symmetry of entropy, was proposed to extract the global color feature. Then color spatial distribution entropy vector for each color channel was also introduced to represent the spatial color information. After that, the moments were adopted to reduce the dimension of color spatial distribution entropy. In the end, a low dimensional vector which includes the global and spatial information was used as index for color image retrieval. The experiment results show that the new method gives better performance than color histogram.

Remote Sensing Technology and Application

• A method for fire detection using Landsat 8 data

  HE Yang, YANG Jin, MA Yong, LIU Jian-Bo, CHEN Fu, LI Xin-Peng, YANG Yi-Fei

  2016,35(5):600-609, DOI: 10.11972/j.issn.1001-9014.2016.05.015

  Abstract: (3457) HTML (239) PDF (5.05 MKB)(10110)

  Abstract:

  Traditional fire detection methods use the high temperature emission characteristics in mid or thermal infrared bands of the MODIS or AVHRR data to extract burning area. It is very hard for these methods to identify small fire regions such as sub-pixel due to the limitation of spatial resolution. Recently researchers have found that shortwave infrared (SWIR) data can also be used to identify and detect high temperature targets. Compared with the thermal infrared data, SWIR has a big discrimination against different features with different temperature. Thus it can identify accurately the location of high temperature targets. In this paper, we acquired fire point products by using Landsat-8 OLI data which has spatial resolution up to 30 m. The main procedure includes two steps. The improved Normalized Burning Ratio Short-wave(NBRS) is calculated at first to adaptively acquire suspected fire points based on the spectral characteristics of fire points in the near infrared and shortwave infrared. Then most false positive points are excluded based on the relationship between peak value in shortwave infrared band of fire points. This algorithm is capable of detecting the burning area around 10% in one pixel. With the premise of avoiding the interference of cloud and constructions, it can also keep a nearly 90% accuracy and low missing rate around 10%.

Infrared Materials and Devices

• Graphene oxide: progress in preparation, reduction and application

  ZHANG Qian, TANG Li-Bin, LI Ru-Jie, XIANG Jin-Zhong, HUANG Qiang, LIU Shu-Ping

  2019,38(1):79-90, DOI: 10.11972/j.issn.1001-9014.2019.01.014

  Abstract: (2894) HTML (215) PDF (4.42 MKB)(9478)

  Abstract:

  With the rapid development of graphene industry, graphene oxide has attracted much attention as an important intermediate product for the preparation of graphene. Due to its excellent physical and chemical properties, it has been widely used in multitudinous fields. Various structural models, preparation methods, properties and related applications, as well as the reduction of graphene oxide are summarized. The choice of oxidants and reduction agents were found to be important in the reaction. The basic selective principles are discussed after comparing various methods. Finally, it is pointed out that there are still some problems to be solved in the preparation and reduction of graphene oxide. The prospect of graphene oxide on its development and influence will also be evaluated.

• RESEARCH ON ELECTRO-INDUCED BIREFRINGENCE IN CRYSTAL SILICON

  ZHANG Yu-Hong, CHEN Zhan-Guo, JIA Gang, SHI Bao, REN Ce, LIU Xiu-Huan, WU Wen-Qing

  2008,27(3):165-169, DOI:

  Abstract: (7780) HTML (181) PDF (466.11 KKB)(9334)

  Abstract:

  首次测量了硅材料在1.3μm波长处,基于克尔效应和弗朗兹-凯尔迪什效应的电致双折射,进而计算出三阶非线性极化率张量X(3)的分量X(3)xyxy.观测到弗朗兹-凯尔迪什效应引起的折射率变化与入射光的偏振态有关.在实验中,测得了由克尔效应引起的折射率之差为⊿n=5.49×10-16E20,而弗朗兹-凯尔迪什效应引起的折射率之差为⊿n'=2.42×10-16E2.50.

Terahertz and Millimeter Wave Technology

• Design and experimental verification of band-pass frequency selective surface based on metamaterial effective medium theory

  WU Xiang, PEI Zhi-Bin, QU Shao-Bo, XU Zhuo, ZHANG Jie-Qiu, MA Hua, WANG Jia-Fu, WANG Xin-Hua, ZHOU Hang

  2011,30(5):469-474, DOI:

  Abstract: (2535) HTML (131) PDF (1.09 MKB)(9119)

  Abstract:

  By adjusting the effective permittivity of the unit cell, a new method of constructing metamaterial band-pass frequency selective surface was proposed. The effective permittivity of continuous conducting wires is negative below the plasma frequency and thus a stop-band occurs. By combining the continuous conducting wires with cut wires, we realized a one-dimensional frequency selective surface. Both the theory analysis and simulation results demonstrated the facility and feasibility of the method. We also designed a wide-angle and polarization-independent frequency selective surface based on this method. Two samples were fabricated to validate the proposed method; the experiment results were fairly consistent with the simulation results. The proposed method eliminates the complicated calculation and excessive parameter optimization process. It paves a new way of designing frequency selective surfaces and is of important reference values for fabricating THz frequency selective surface as well as multi-band, tunable and miniaturized frequency selective surfaces.

• METHOD OF SCATTERING CENTER ESTIMATION BY RADAR TARGET FREQUENCY RESPONSE DATA IN CLUTTER ENVIRONMENT

  JIANG Wei Dong CHEN Zen Ping ZHUANG Zhao Wen GUO Gui Rong

  2001,20(2):111-116, DOI:

  Abstract: (824) HTML (103) PDF (331.55 KKB)(8968)

  Abstract:

  The simulation methods of radar clutter with given amplitude distribution and power spectrum were described, and the simulation results of radar clutter were given. A scattering center model of frequency domain of radar target was presented under the clutter environment and its solution method was studied. Finally, the experimental results of simulation data and the measurement data of aircraft scale model were given.

• IMAGE FUSION SCHEME OF PIXEL-LEVEL AND MULTI-OPERATOR FOR INFRARED AND VISIBLE LIGHT IMAGES

  LIU Gui Xi YANG Wan Hai

  2001,20(3):207-210, DOI:

  Abstract: (1179) HTML (111) PDF (196.71 KKB)(8961)

  Abstract:

  A novel pixel level image fusion scheme was presented based on multiscale decompositon. First, the wavelet transform is used to perform a multiscale decomposition of each image. Then, the wavelet coefficients of fused image are constructed using multiple operators according to different fusion rules. This approach is successfully used to fuse the infrared and visible light images. The experimental results show that the fusion scheme is effective and the fused images are more suitable for human visual or machine perception.

Terahertz and Millimeter Wave Technology

• Passive millimeter wave focal plane array imaging technology

  WANG Nan-Nan, QIU Jing-Hui, ZHANG Peng-Yu, DENG Wei-Bo

  2011,30(5):419-424, DOI:

  Abstract: (3579) HTML (195) PDF (1.64 MKB)(8955)

  Abstract:

  Under the background of safety inspection, the key technologies of near-range passive millimeter wave focal plane array imaging are studied. The analysis of the system quasi-optics were carried out using fundamental Gaussian beam method combined with geometrical optics method. A multi-beam wide-angle scanning lens antenna was designed. A new dielectric rod antenna was devised, which is prone to be aligned in close arrays and provide good radiation to the lens. Miniaturized direct-detection radiometers were fabricated with high-sensitive in Ka-band . Experimental results of the 20-channel passive millimeter wave focal plane array imaging system are presented, which can be used to detect hidden objects on human bodies in near range indoors.

Image Processing and Software Simulation

• HYPERSPECTRAL ANOMALY DETECTION ALGORITHM BASED ON BACKGROUND RESIDUAL ERROR DATA

  LI Jie, ZHAO Chun-Hui, MEI Feng

  2010,29(2):150-151, DOI:

  Abstract: (2476) HTML (62) PDF (571.44 KKB)(8667)

  Abstract:

  In order to overcome the serious background interferences for small target detection of hyperspectral imagery, a nonlinear anomaly detection algorithm based on the background residual error data was proposed. After the background endmembers were extracted, spectral unmixing technique was applied to all mixed spectral pixels to separate target information from complicated background clutter.Then, the unmixing residual error data that included abundant target information was mapped into a high-dimensional feature space by a nonlinear mapping function. Nonlinear information between the spectral bands of hyperspectral imagery was exploited and the anomaly targets could be detected by using RX operator in the feature space. Thus, the ninlinear statistical characteristics between the hyperspectral bands were used effectively on the basis of suppressing the large probability background information. Numerical experiments were conducted on real AVIRIS data to validate the effectiveness of the proposed algorithm. The detection results were compared with those detected by the classical RX algorithm and KRS which did not suppress the backguound information. The results show that the proposed algorithm has better detection performance, lower false alarm probability and lower computational complexity than other detection algorithms.