Journal Description
Photonics
Photonics
is an international, scientific, peer-reviewed, open access journal on the science and technology of optics and photonics, published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15.5 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journal: Optics.
Impact Factor:
2.4 (2022);
5-Year Impact Factor:
2.4 (2022)
Latest Articles
Refractive Index and Dispersion Measurement Principle with Polarization Change in Total Internal Reflection
Photonics 2024, 11(6), 505; https://doi.org/10.3390/photonics11060505 (registering DOI) - 25 May 2024
Abstract
Refractive index measurements have been an important task for a long time because that index plays an essential role in describing the optical properties of a material. Many methods have been developed to perform that task. Some of them use interferometry to achieve
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Refractive index measurements have been an important task for a long time because that index plays an essential role in describing the optical properties of a material. Many methods have been developed to perform that task. Some of them use interferometry to achieve high precision. However, these configurations are complicated. Some measure the critical angle using simple structures, but their accuracy is unsatisfactory because it is difficult to judge the exact critical angle with intensity variations. Here, we propose several new schemes based on measuring the polarization change in the total internal reflection. The proposed method has the merits of simple structure and easy incident angle determination that gives the maximum phase change. Additionally, it is possible to find the material dispersion by measuring the wavelength dependence of the polarization ellipticity. Some useful formulas relating the refractive index to the maximum phase change are obtained. This work can provide valuable alternatives for refractive index measurement.
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(This article belongs to the Special Issue Advanced Photonic Sensing and Measurement II)
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A New Algorithm to Mitigate Fragmentation and Crosstalk in Multi-Core Elastic Optical Networks
by
Jurandir C. Lacerda, Jr., Aline G. Morais, Adolfo V. T. Cartaxo and André C. B. Soares
Photonics 2024, 11(6), 504; https://doi.org/10.3390/photonics11060504 (registering DOI) - 25 May 2024
Abstract
This paper proposes a core and spectrum allocation algorithm for elastic optical networks based on multi-core fibers. In this context, the fragmentation and crosstalk mitigation algorithm (FraCA) is proposed. FraCA implements mechanisms to reduce spectral fragmentation and inter-core crosstalk in the network, proving
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This paper proposes a core and spectrum allocation algorithm for elastic optical networks based on multi-core fibers. In this context, the fragmentation and crosstalk mitigation algorithm (FraCA) is proposed. FraCA implements mechanisms to reduce spectral fragmentation and inter-core crosstalk in the network, proving efficient when compared with six other algorithms reported in the literature. The numerical results show that when compared with the most competitive of the six algorithms, FraCA achieves a gain of request blocking probability of at least 16.87%, a gain of bandwidth blocking probability of at least 43.95%, and a mean increase in spectral utilization of at least 4.36%.
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(This article belongs to the Special Issue Recent Advances for Next-Generation High-Speed Optical Networks: Technologies, Components, Systems and Architectures)
Open AccessArticle
Ultra-Sensitive Refractive Index Sensing Based on Quasi-BICs in All-Dielectric Nanorod Array
by
Yuefeng Zhao, Zhenghua Wu, Zhihao Feng and Tingyin Ning
Photonics 2024, 11(6), 503; https://doi.org/10.3390/photonics11060503 (registering DOI) - 25 May 2024
Abstract
We propose an all-dielectric nanorod array for ultra-sensitive refractive index sensing based on quasi-bound states in the continuum (BICs). The nanorod is fabricated by silicon or silicon with an air hole, i.e., the hollow silicon nanorod. The quasi-BICs are formed in the hollow
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We propose an all-dielectric nanorod array for ultra-sensitive refractive index sensing based on quasi-bound states in the continuum (BICs). The nanorod is fabricated by silicon or silicon with an air hole, i.e., the hollow silicon nanorod. The quasi-BICs are formed in the hollow silicon nanorod array due to the symmetry-breaking of air holes. The high-quality factor (Q-factor) and ultra-narrow reflectance spectral width at quasi-BICs contribute to high performances of the sensor. The numerical results show that the sensitivity and figure of merit (FOM) can reach up to 602.9 nm/RIU and 34,977, respectively. The results indicate that the proposed nanostructures of quasi-BICs are promising for advanced biosensing applications.
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(This article belongs to the Section Lasers, Light Sources and Sensors)
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Air Core ARROW Waveguides Fabricated in a Membrane-Covered Trench
by
Seth Walker, Holger Schmidt and Aaron R. Hawkins
Photonics 2024, 11(6), 502; https://doi.org/10.3390/photonics11060502 (registering DOI) - 25 May 2024
Abstract
We report the design, fabrication, and characterization of hollow-core anti-resonant reflecting optical waveguides (ARROWs) fabricated in a membrane-covered trench. These structures are built on silicon wafers using standard microfabrication techniques, including plasma etching, to form trenches. Four waveguide designs are demonstrated, which have
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We report the design, fabrication, and characterization of hollow-core anti-resonant reflecting optical waveguides (ARROWs) fabricated in a membrane-covered trench. These structures are built on silicon wafers using standard microfabrication techniques, including plasma etching, to form trenches. Four waveguide designs are demonstrated, which have different numbers of thin-film reflecting layers. We demonstrate that optical loss decreases with additional reflecting layers, with measured loss coefficients as low as 1 cm−1.
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(This article belongs to the Special Issue Integrated Waveguide-Based Photonic Devices)
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High-Performance Fiber Ring Laser Based on Polarization Space Parity-Time Symmetry Breaking
by
Fengling Zhang, Zhengmao Wu, Xin Tong and Guangqiong Xia
Photonics 2024, 11(6), 501; https://doi.org/10.3390/photonics11060501 (registering DOI) - 25 May 2024
Abstract
This work proposes and experimentally demonstrates a high-performance polarization space parity-time (PT) symmetric fiber ring laser to achieve a low-noise, narrow-linewidth, and highly stable single-longitudinal-mode output. The gain/loss and coupling coefficients are regulated by adjusting a polarization controller (PC) and the pumping current
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This work proposes and experimentally demonstrates a high-performance polarization space parity-time (PT) symmetric fiber ring laser to achieve a low-noise, narrow-linewidth, and highly stable single-longitudinal-mode output. The gain/loss and coupling coefficients are regulated by adjusting a polarization controller (PC) and the pumping current of an erbium-doped fiber amplifier (EDFA) within the ring cavity. The results show that the single longitudinal mode oscillation of the laser can be implemented by PT symmetry breaking. The frequency noise spectral density and the linewidth characteristics of the laser are evaluated by the short-delay self-heterodyne method. The results reveal that excellent low-frequency noise (181 Hz2/Hz at a 10 kHz offset frequency) and narrow fundamental linewidth (68 Hz) can be achieved. Additionally, the laser exhibits outstanding stability with only 0.64 pm wavelength drift over 30 min. By tuning an optical tunable filter (OTF), the wavelength tunable range of the laser can cover the entire C-band. Furthermore, the impacts of different fiber length on the frequency noise spectral density and the filter bandwidth on stability are analyzed, offering guidance for component selection in such laser systems.
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(This article belongs to the Special Issue Advanced Lasers and Their Applications II)
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Open AccessArticle
Camera-Based Safety System for Optical Wireless Power Transmission Using Dynamic Safety-Distance
by
Chen Zuo and Tomoyuki Miyamoto
Photonics 2024, 11(6), 500; https://doi.org/10.3390/photonics11060500 - 24 May 2024
Abstract
This paper introduces a new safety approach for Optical Wireless Power Transmission (OWPT), a technology that is integral to the new kinds of Wireless Power Transmission technology (WPT). It starts from the fundamental configuration of the current OWPT system, addressing the safety concerns
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This paper introduces a new safety approach for Optical Wireless Power Transmission (OWPT), a technology that is integral to the new kinds of Wireless Power Transmission technology (WPT). It starts from the fundamental configuration of the current OWPT system, addressing the safety concerns related to lasers by involving laser irradiation hazards, laser exposure regulation and guidelines, and a comparison with other safety methods. A camera-based OWPT safety system focused on the emission control of the light source is proposed, and it utilizes a depth camera and finely tuned computer vision-based control program. Through meticulous system design and experiments, the proposed system can detect moving objects in a limited indoor environment and control the laser/LED light transmission according to the object’s velocity dynamically. Various functions and exclusive improvements towards OWPT operation are mentioned, and Dynamic Safety-Distance is proposed as the core mechanism of the safety system. Through on-site experiments, indoor safety control and system operation’s evaluation are discussed, acknowledging both the advantages and limitations of the proposed safety system. This paper concludes with suggestions for further developments in camera-based OWPT safety incorporating the concept of Automatic Emission Control.
Full article
(This article belongs to the Special Issue Latest Papers Related to OWPT 2024 on the Topics of Devices, Components and Systems)
Open AccessCommunication
Simulation Study of Localized, Multi-Directional Continuous Dynamic Tailoring for Optical Skyrmions
by
Gao Tang, Chunyan Bai, Yuxing Zhang, Zhening Zhao and Dawei Zhang
Photonics 2024, 11(6), 499; https://doi.org/10.3390/photonics11060499 - 24 May 2024
Abstract
The topological properties of optical skyrmions have enormous application value in fields such as optical communication and polarization sensing. At present, research on optical skyrmions focuses primarily on the topological principles of skyrmions and their applications. Nonetheless, extant research devoted to skyrmion-array manipulation
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The topological properties of optical skyrmions have enormous application value in fields such as optical communication and polarization sensing. At present, research on optical skyrmions focuses primarily on the topological principles of skyrmions and their applications. Nonetheless, extant research devoted to skyrmion-array manipulation remains meager. The sole manipulation scheme has a limited effect on the movement direction of the whole skyrmion array. Based on the interference principle of the surface plasmon polariton (SPP) wave, we propose an upgraded scheme for the tailoring of electric-field optical skyrmions. A distributed Gaussian-focused spots array is deployed. Unlike the existing manipulation, we customize the phase of the light source to be more flexible, and we have discovered optical-skyrmion tailoring channels and shaping channels. Specifically, we move the skyrmions within the channel in both directions and manipulate the shape of the topological domain walls to achieve customized transformation. This work will evolve towards a more flexible regulatory plan for tailoring optical-skyrmion arrays, and this is of great significance for research in fields such as optical storage and super-resolution microimaging.
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(This article belongs to the Special Issue Optoelectronic Detection Technologies and Applications)
Open AccessArticle
Performance Analysis of Six Electro-Optical Crystals in a High-Bandwidth Traveling Wave Mach-Zehnder Light Modulator
by
Abtin Ataei, Paul McManamon and Andrew Sarangan
Photonics 2024, 11(6), 498; https://doi.org/10.3390/photonics11060498 - 24 May 2024
Abstract
In this study, a traveling wave Mach-Zehnder intensity modulator (TW-MZM) was designed and optimized for six different electro-optical (EO) crystals: lithium niobate (LNB), potassium niobate (KNB), lithium titanate (LTO), beta barium borate (BBO), cadmium telluride (CdTe), and indium phosphide (InP). The performance of
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In this study, a traveling wave Mach-Zehnder intensity modulator (TW-MZM) was designed and optimized for six different electro-optical (EO) crystals: lithium niobate (LNB), potassium niobate (KNB), lithium titanate (LTO), beta barium borate (BBO), cadmium telluride (CdTe), and indium phosphide (InP). The performance of each EO crystal, including optical and radio frequency (RF) loss, applied voltage, and modulation bandwidth, was estimated and compared. The results suggest that, in theory, KNB, LTO, BBO, and CdTe have the potential to outperform LNB. However, it should be noted that the loss associated with KNB and LTO is comparable to that of LNB. The findings demonstrated that BBO and CdTe exhibit a modulation bandwidth exceeding 100 GHz and demonstrate the lowest loss among the considered crystals based on the assumed geometry.
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(This article belongs to the Section Optoelectronics and Optical Materials)
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Tunable Near-Infrared Transparent Bands Based on Cascaded Fabry–Perot Cavities Containing Phase Change Materials
by
Yuchun She, Kaichan Zhong, Manni Tu, Shuyuan Xiao, Zhanxu Chen, Yuehua An, Dejun Liu and Feng Wu
Photonics 2024, 11(6), 497; https://doi.org/10.3390/photonics11060497 - 24 May 2024
Abstract
In this paper, we construct a near-infrared Fabry–Perot cavity composed of two sodium (Na) layers and an antimony trisulfide (Sb2S3) layer. By cascading two Fabry–Perot cavities, the transmittance peak splits into two transmittance peaks due to the coupling between
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In this paper, we construct a near-infrared Fabry–Perot cavity composed of two sodium (Na) layers and an antimony trisulfide (Sb2S3) layer. By cascading two Fabry–Perot cavities, the transmittance peak splits into two transmittance peaks due to the coupling between two Fabry–Perot modes. We utilize a coupled oscillator model to describe the mode coupling and obtain a Rabi splitting of 60.0 meV. By cascading four Fabry–Perot cavities, the transmittance peak splits into four transmittance peaks, leading to a near-infrared transparent band. The near-infrared transparent band can be flexibly tuned by the crystalline fraction of the Sb2S3 layers. In addition, the effects of the layer thickness and incident angle on the near-infrared transparent band and the mode coupling are investigated. As the thickness of the Na layer increases, the coupling strength between the Fabry–Perot modes becomes weaker, leading to a narrower transparent band. As the thickness of the Sb2S3 layer increases, the round-trip propagating of the Sb2S3 layer increases, leading to the redshift of the transparent band. As the incident angle increases, the round-trip propagating of the Sb2S3 layer decreases, leading to the blueshift of the transparent band. This work not only provides a viable route to achieving tunable near-infrared transparent bands, but also possesses potential applications in high-performance display, filtering, and sensing.
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(This article belongs to the Special Issue Photonic Crystals: Physics and Devices)
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Manchester Return-to-Zero On–Off Keying Modulation for Free-Space Optical Communication
by
Wenhao Zong, Qianwen Jing, Minfang Liu, Yan Gao and Yanqing Hong
Photonics 2024, 11(6), 496; https://doi.org/10.3390/photonics11060496 - 24 May 2024
Abstract
This paper proposes a Manchester return-to-zero on–off keying (M-RZ-OOK) modulation for free-space optical (FSO) communication. M-RZ-OOK modulation is achieved by introducing Manchester coding into the RZ-OOK format. M-RZ-OOK has the features of phase-flipped impulse series in the spectrum. Therefore, normal and inversed channel
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This paper proposes a Manchester return-to-zero on–off keying (M-RZ-OOK) modulation for free-space optical (FSO) communication. M-RZ-OOK modulation is achieved by introducing Manchester coding into the RZ-OOK format. M-RZ-OOK has the features of phase-flipped impulse series in the spectrum. Therefore, normal and inversed channel state information (CSI) can be extracted by applying a local oscillator (LO) with the frequencies of impulses, respectively. These extracted CSIs can be applied to realize adaptive threshold decision (ATD) and adaptive power transmission (APT) in the forward and backward links simultaneously. The proposed M-RZ-OOK modulation was verified in simulations using various turbulence channels. The simulation results demonstrated that ATD and APT were effectively accomplished in the forward and backward links with the estimated normal and inversed CSIs.
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(This article belongs to the Special Issue Free-Space Optical Communication and Networking Technology)
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Open AccessReview
A Review of Optical Parametric Amplification at the Vulcan Laser Facility
by
Samuel Buck, Pedro Oliveira, Theodoros Angelides and Marco Galimberti
Photonics 2024, 11(6), 495; https://doi.org/10.3390/photonics11060495 - 23 May 2024
Abstract
An overview of Optical Parametric Chirped Pulse Amplification (OPCPA) is given as the basis for the next generation of ultra-intense laser systems (> W/cm ). The benefits and drawbacks of OPCPA are discussed to explain the choice behind
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An overview of Optical Parametric Chirped Pulse Amplification (OPCPA) is given as the basis for the next generation of ultra-intense laser systems (> W/cm ). The benefits and drawbacks of OPCPA are discussed to explain the choice behind the decisions for the direction of the Central Laser Facility’s (CLF) upcoming Vulcan 20-20 project. A history of OPCPA use at the CLF is described to surmise the foundation of the confidence in this technology for Vulcan 20-20; a 20 PW user facility for high-intensity plasma physics.
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(This article belongs to the Special Issue Recent Advances in Optical Parametric Amplifiers)
Open AccessReview
Integrated Photonic Passive Building Blocks on Silicon-On-Insulator Platform
by
Francesco Amanti, Greta Andrini, Fabrizio Armani, Fabrizio Barbato, Vittorio Bellani, Vincenzo Bonaiuto, Simone Cammarata, Matteo Campostrini, Thu Ha Dao, Fabio De Matteis, Valeria Demontis, Simone Donati, Giovanni Di Giuseppe, Sviatoslav Ditalia Tchernij, Andrea Fontana, Jacopo Forneris, Luca Frontini, Roberto Gunnella, Simone Iadanza, Ali Emre Kaplan, Cosimo Lacava, Valentino Liberali, Leonardo Martini, Francesco Marzioni, Luca Morescalchi, Elena Pedreschi, Paolo Piergentili, Domenic Prete, Valentino Rigato, Carlo Roncolato, Francesco Rossella, Matteo Salvato, Fausto Sargeni, Jafar Shojaii, Franco Spinella, Alberto Stabile, Alessandra Toncelli and Valerio Vitaliadd
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Photonics 2024, 11(6), 494; https://doi.org/10.3390/photonics11060494 - 23 May 2024
Abstract
Integrated photonics on Silicon-On-Insulator (SOI) substrates is a well developed research field that has already significantly impacted various fields, such as quantum computing, micro sensing devices, biosensing, and high-rate communications. Although quite complex circuits can be made with such technology, everything is based
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Integrated photonics on Silicon-On-Insulator (SOI) substrates is a well developed research field that has already significantly impacted various fields, such as quantum computing, micro sensing devices, biosensing, and high-rate communications. Although quite complex circuits can be made with such technology, everything is based on a few ’building blocks’ which are then combined to form more complex circuits. This review article provides a detailed examination of the state of the art of integrated photonic building blocks focusing on passive elements, covering fundamental principles and design methodologies. Key components discussed include waveguides, fiber-to-chip couplers, edges and gratings, phase shifters, splitters and switches (including y-branch, MMI, and directional couplers), as well as subwavelength grating structures and ring resonators. Additionally, this review addresses challenges and future prospects in advancing integrated photonic circuits on SOI platforms, focusing on scalability, power efficiency, and fabrication issues. The objective of this review is to equip researchers and engineers in the field with a comprehensive understanding of the current landscape and future trajectories of integrated photonic components on SOI substrates with a 220 nm thick device layer of intrinsic silicon.
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(This article belongs to the Special Issue Photonic Integrated Circuits for Information, Computing and Sensing)
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Open AccessArticle
Acquiring Gamma-Ray Energy Spectrum Using a Plastic Scintillation Optical Fiber Detector
by
Siwon Song, Jae Hyung Park, Jinhong Kim, Seunghyeon Kim, Seokhyeon Jegal, Sangjun Lee and Bongsoo Lee
Photonics 2024, 11(6), 493; https://doi.org/10.3390/photonics11060493 - 23 May 2024
Abstract
The plastic scintillation optical fiber (PSOF) detector, characterized by its large contact area with measurement targets, effectively detects and quantifies radiation in diverse radiation-contaminated areas and liquid environments. While it is extensively utilized for measuring alpha, beta, gamma, and neutron radiations, comprehensive documentation
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The plastic scintillation optical fiber (PSOF) detector, characterized by its large contact area with measurement targets, effectively detects and quantifies radiation in diverse radiation-contaminated areas and liquid environments. While it is extensively utilized for measuring alpha, beta, gamma, and neutron radiations, comprehensive documentation on the spectrum measurement and energy calibration methods for gamma nuclides has not been reported. Accurate energy calibration is crucial for the precise quantification of radiation doses from various sources. The pulse-height spectrum produced by the PSOF detector does not display a Compton maximum because of the significant Gaussian energy broadening. Additionally, this spectrum compresses as the distance increases between the radiation source and the light measurement device. In this study, the energy spectrum of a PSOF for gamma nuclides was characterized by energy calibrations using Compton edge (CE). The CE channel in the measurement spectrum of the PSOF detector for three gamma nuclides was identified using the first-order differentiation method. This technique was successfully applied to spectra measured at various radiation source positions to determine the attenuation coefficients. The proposed energy calibration method allows for the conversion of pulse-height spectra obtained from alpha, beta, and neutron radiation measured with PSOF detectors into energy spectra.
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(This article belongs to the Special Issue Optical Fibre Sensing: Recent Advances and Future Perspectives)
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Study of Reducing Atmospheric Turbulence-Induced Beam Wander of a Twisted Electromagnetic Elliptical Vortex Beam
by
Kai Huang, Yonggen Xu, Yuqiang Li and Jin Cao
Photonics 2024, 11(6), 492; https://doi.org/10.3390/photonics11060492 - 22 May 2024
Abstract
We derive the analytical expressions for root-mean-square (rms) beam wander (BW) and relative BW of a twisted electromagnetic elliptical vortex (TEEV) beam propagating through non-Kolmogorov atmospheric turbulence with the help of the extended Huygens–Fresnel principle and the second-order moments of the Wigner distribution
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We derive the analytical expressions for root-mean-square (rms) beam wander (BW) and relative BW of a twisted electromagnetic elliptical vortex (TEEV) beam propagating through non-Kolmogorov atmospheric turbulence with the help of the extended Huygens–Fresnel principle and the second-order moments of the Wigner distribution function (WDF). Our numerical findings demonstrate that the BW of a TEEV beam with a small ellipticity, a large topological charge as well as a small waist width and initial coherent length is less affected by the turbulence. It can be also found that the effect of turbulence with a larger outer scale of turbulence, a generalized exponent parameter, and a generalized structure parameter on BW is more obvious. It is interesting to find that the effect of atmospheric turbulence on BW for a TEEV beam can be effectively reduced by regulating jointly the symbols and sizes of the twisted factor and topological charge. Therefore, modulation of the structure parameters of a TEEV beam provides a new way to mitigate turbulence-induced beam wander. Our work will be useful for free-space optical communications, remote sensing, and lidar distance measurement.
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(This article belongs to the Special Issue Coherence Properties of Light: From Theory to Applications)
Open AccessReview
A Review of Light-Emitting Diodes and Ultraviolet Light-Emitting Diodes and Their Applications
by
Trailokya Bhattarai, Abasifreke Ebong and Mohammad Yasin Akhtar Raja
Photonics 2024, 11(6), 491; https://doi.org/10.3390/photonics11060491 - 22 May 2024
Abstract
This paper presents an extensive literature review on Light-Emitting Diode (LED) fundamentals and discusses the historical development of LEDs, focusing on the material selection, design employed, and modifications used in increasing the light output. It traces the evolutionary trajectory of the efficiency enhancement
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This paper presents an extensive literature review on Light-Emitting Diode (LED) fundamentals and discusses the historical development of LEDs, focusing on the material selection, design employed, and modifications used in increasing the light output. It traces the evolutionary trajectory of the efficiency enhancement of ultraviolet (UV), blue, green, and red LEDs. It rigorously examines the diverse applications of LEDs, spanning from solid-state lighting to cutting-edge display technology, and their emerging role in microbial deactivation. A detailed overview of current trends and prospects in lighting and display technology is presented. Using the literature, this review offers valuable insights into the application of UV LEDs for microbial and potential viral disinfection. It conducts an in-depth exploration of the various microorganism responses to UV radiation based on the existing literature. Furthermore, the review investigates UV LED-based systems for water purification and surface disinfection. A prospective design for a solar-powered UV LED disinfection system is also delineated. The primary objective of this review article is to organize and synthesize pivotal information from the literature, offering a concise and focused overview of LED applications. From our review, we can conclude that the efficiency of LEDs has continuously increased since its invention and researchers are searching for methods to increase efficiency further. The demand for LED lighting and display applications is continuously increasing. Our analysis reveals an exciting horizon in microbial disinfection, where the integration of UV LED systems with cutting-edge technologies such as sensors, solar power, Internet-of-Things (IoT) devices, and artificial intelligence algorithms promises high levels of precision and efficacy in disinfection practices. This contribution sets the stage for future research endeavors in the domain of viral disinfection using solar-powered UV LED modules for universal applications.
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(This article belongs to the Section Lasers, Light Sources and Sensors)
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Real-Time Tracking of Photovoltaics by Differential Absorption Imaging in Optical Wireless Power Transmission
by
Kaoru Asaba and Tomoyuki Miyamoto
Photonics 2024, 11(6), 490; https://doi.org/10.3390/photonics11060490 - 22 May 2024
Abstract
In the future, wireless power transmission is expected to cover power levels ranging from milliwatts to megawatts and over distances of a few meters to kilometers for both stationary and moving photovoltaic (PV) targets. Optical wireless power transmission (OWPT) is a promising solution
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In the future, wireless power transmission is expected to cover power levels ranging from milliwatts to megawatts and over distances of a few meters to kilometers for both stationary and moving photovoltaic (PV) targets. Optical wireless power transmission (OWPT) is a promising solution for such multi-scale systems, which use the narrow beam divergence of light. To enhance the efficiency of power generation in PV targets, real-time detection of the target’s position and attitude is crucial for OWPT systems. The authors propose detecting the PV using differential absorption images as one such method. This paper investigates algorithms for tracking moving PV targets and evaluates their performance. The first algorithm combines thresholds with an autoregressive (AR) model, while the other two use estimation with Kalman filters. The comparison of tracking algorithms can be undertaken using a score function based on the position estimation error. The evaluation results indicate that the AR model combined with thresholds, on average, outperforms the other models. There was no significant difference between the approach involving use of a Kalman filter to estimate positions based on a uniform motion model and the approach involving use of a Kalman filter to estimate the AR model. The authors’ series of studies, from a former high-level requirement study to the current target tracking using differential absorption imaging, has verified a concept for one of the crucial processes in OWPT. These works form a step toward the practical implementation of OWPT systems.
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(This article belongs to the Special Issue Latest Papers Related to OWPT 2024 on the Topics of Devices, Components and Systems)
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Open AccessReview
Stimulated Raman Scattering Microscopy: A Review
by
Rajeev Ranjan and Luigi Sirleto
Photonics 2024, 11(6), 489; https://doi.org/10.3390/photonics11060489 - 22 May 2024
Abstract
Stimulated Raman scattering (SRS) microscopy is a high-speed imaging modality based on intrinsic molecular vibrations, producing chemical maps in living systems. Such capability, allowing for direct visualization without the perturbation of biological processes, has enabled a plethora of biological and medical applications. In
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Stimulated Raman scattering (SRS) microscopy is a high-speed imaging modality based on intrinsic molecular vibrations, producing chemical maps in living systems. Such capability, allowing for direct visualization without the perturbation of biological processes, has enabled a plethora of biological and medical applications. In this review, after introducing the basic theory and competitive effects of SRS, some crucial features for SRS microscopy implementations, such as noise, spectral bandwidth, speed, chemical sensitivity, spatial resolution, and quantum enhancement, are discussed. Finally, some SRS applications in biological and medical imaging are described. Even if certainly not exhaustive, we aimed to offer a broad overview, providing guidance for newcomers and hinting at a more detailed investigation to interested researchers in this rapidly growing field.
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(This article belongs to the Special Issue Editorial Board Members' Collection Series: Nonlinear Photonics)
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Open AccessArticle
Repeatable Passive Fiber Optic Coupling of Single-Mode Waveguides in High-Precision Disposable Photonic Biosensors
by
Jakob Reck, Laurids von Emden, Klara Mihov, Martin Kresse, Madeleine Weigel, Tianwen Qian, Csongor Keuer, Philipp Winklhofer, Marcel Amberg, David de Felipe, Crispin Zawadzki, Moritz Kleinert, Norbert Keil and Martin Schell
Photonics 2024, 11(6), 488; https://doi.org/10.3390/photonics11060488 - 21 May 2024
Abstract
This research demonstrates a method for the repeatable passive fiber optic coupling of single-mode waveguides with a micron-scale accuracy for high-precision disposables. The aim is to broaden the application of photonic integrated circuits (PICs) from traditional fiber optic communication systems to include medical,
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This research demonstrates a method for the repeatable passive fiber optic coupling of single-mode waveguides with a micron-scale accuracy for high-precision disposables. The aim is to broaden the application of photonic integrated circuits (PICs) from traditional fiber optic communication systems to include medical, life science, and environmental sensing applications. The proposed passive coupling system enables the straightforward and reliable interchange of disposable photonic chips without manual read-out unit adjustments. Robustness is attributed to the chip-side grating couplers with 3 dB coupling tolerances exceeding ± 25 µm and a mechanical three-groove kinematic method ensuring precise alignment. The system simplicity is highlighted by the simple manual insertion and fixation of silicon nitride (Si3N4) PICs on a carrier using magnetic force and passive alignment features. Testing on a batch of 99 identical yet independent units revealed a standard deviation (SD) of 5.1 dB in coupling loss, without realignment post-calibration. This eliminates the need for active alignment processes, showing its potential for enabling field use. A usability assessment with five untrained operators confirms the suitability for various end-users, with consistent performance in engaging and disengaging disposable PICs. The research significantly advances the integration of photonic sensor technology into practical applications, particularly for chemical and biological fluid analysis in point-of-care settings.
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(This article belongs to the Special Issue Advanced Photonic Sensing and Measurement II)
Open AccessArticle
Illuminating Life Sciences: A Biophysical Guide to the Use of Chromatic and White Light Sources in Photobiology
by
Mira Mutschlechner and Harald Schöbel
Photonics 2024, 11(6), 487; https://doi.org/10.3390/photonics11060487 - 21 May 2024
Abstract
With the increasing availability of LEDs, researchers in photobiology have easier access to customized light sources. However, the abundance of different light sources poses new challenges for the correct characterization of existing light conditions. The photobiological effect of a light source depends mainly
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With the increasing availability of LEDs, researchers in photobiology have easier access to customized light sources. However, the abundance of different light sources poses new challenges for the correct characterization of existing light conditions. The photobiological effect of a light source depends mainly on the number of photons involved and the spectral composition. However, light sources are mainly described by parameters such as radiant flux, dominant or peak wavelength, and correlated color temperature (CCT). Therefore, in this work, chromatic and white light sources were measured for their spectral composition, various characterization parameters were determined, and the resulting photon flux densities were calculated, focusing on dominant versus peak wavelength for chromatic LEDs and the CCT for white LEDs and fluorescent tubes. The use of the dominant wavelength is inappropriate as it is partly outside the actual spectral range. It was also shown that white light sources with the same CCT have significantly different spectral compositions and, therefore, may have different photobiological effects. The results of this work should serve as a basis for life scientists to better compare light sources, to correctly interpret existing parameters, and to describe light conditions in a standardized and comparable way.
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(This article belongs to the Special Issue Optical Technologies for Biomedical Science)
Open AccessArticle
Polarimeter Optical Spectrum Analyzer
by
Eyal Buks
Photonics 2024, 11(6), 486; https://doi.org/10.3390/photonics11060486 - 21 May 2024
Abstract
A coherent optical spectrum analyzer is integrated with a rotating quarter wave plate polarimeter. The combined polarimeter optical spectrum analyzer (POSA) allows the extraction of the state of polarization with high spectral resolution. The POSA is used in this work to study two
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A coherent optical spectrum analyzer is integrated with a rotating quarter wave plate polarimeter. The combined polarimeter optical spectrum analyzer (POSA) allows the extraction of the state of polarization with high spectral resolution. The POSA is used in this work to study two optical systems. The first is an optical modulator based on a ferrimagnetic sphere resonator. The POSA is employed to explore the underlying magneto–optical mechanism responsible for modulation sideband asymmetry. The second system under study is a cryogenic fiber loop laser, which produces an unequally spaced optical comb. The polarization measurements provide insights into the nonlinear processes responsible for comb creation. Characterizations extracted from the POSA data provide guidelines for the performance optimization of applications based on the systems under study.
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(This article belongs to the Special Issue High-Power Fiber Lasers)
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