ALBERT

Description:    High-sensitive multi-species detection around 1550 nm using a modulated grating Y-branch, MG-Y, diode laser tunable between 1529 nm and 1565 nm is presented. The MG-Y diode laser is based on the Vernier effect of two modulated gratings, and exhibits quasi-continuous tuning over 36 nm. Multi-species detection is achieved by fast sequential scanning of single absorption lines of CH 4 , CO, C 2 H 2 , and CO 2 distributed over the tuning range of the diode laser. The laser wavelength is scanned about 10 GHz around each absorption line for 5 ms and this is followed by a discrete large jump in operating wavelength to the next line. The MG-Y diode laser has a good repeatability in output frequency between sequential scan segments (〈10 MHz) enabling averaging of the scans. The setup employs digital wavelength modulation spectroscopy, dWMS, with Fourier-based WMS retrieval, applicable through the use of data acquisition cards and coherent sampling. Absorbance sensitivity using 2 f -WMS signals of 7×10 −7 in 30 s (all precisions in this paper are at the 1 σ level) is demonstrated for sensing of four gases and 2×10 −7 when only one gas is detected. Corresponding numbers for 0.5 s of averaging are 4×10 −6 and 1×10 −6 . Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-011-4587-z Authors M. Lewander, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA A. Fried, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA P. Weibring, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA D. Richter, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA S. Spuler, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA L. Rippe, National Center for Atmospheric Research, Earth Observing Laboratory, 3450 Mitchell Lane, Boulder, CO 80301, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    Using the photonic crystal fiber (PCF) with zero dispersion wavelengths of the fundamental mode and the second-order mode at 985 nm and 885 nm designed and fabricated in our lab, the anti-Stokes signals from 586.5 to 558 nm are efficiently generated in the second-order mode. When the pump working wavelength λ 0 increases from 830 to 880 nm and the input average power P in reduces from 43 to 25 mW, the output power of anti-Stokes signal increases 1.76 times, the power ratio of anti-Stokes signal at 558 nm to the residual pump component at 880 nm is estimated as 5:1, and the maximal conversion efficiency P as / P p 0 can be up to 36%. The possible reasons for the difference from theoretical results are discussed. The combined effects of the interval between the pump working wavelength and zero dispersion wavelength and the input power on the signal conversion process are analyzed. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-011-4581-5 Authors J.-H. Yuan, State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), P.O. Box 163, #, BUPT, 100876 Beijing, China X.-Z. Sang, State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), P.O. Box 163, #, BUPT, 100876 Beijing, China C.-X. Yu, State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), P.O. Box 163, #, BUPT, 100876 Beijing, China X.-J. Xin, State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), P.O. Box 163, #, BUPT, 100876 Beijing, China G.-Y. Zhou, Institute of Infrared Optical Fibers and Sensors, Physics Department, Yanshan University, 066004 Qinhuangdao, China S.-G. Li, Institute of Infrared Optical Fibers and Sensors, Physics Department, Yanshan University, 066004 Qinhuangdao, China L.-T. Hou, Institute of Infrared Optical Fibers and Sensors, Physics Department, Yanshan University, 066004 Qinhuangdao, China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    Presently, large efforts are conducted toward the development of highly brilliant γ beams via Compton back scattering of photons from a high-brilliance electron beam, either on the basis of a normal-conducting electron linac or a (super-conducting) Energy Recovery Linac (ERL). Particularly, ERLs provide an extremely brilliant electron beam, thus enabling the generation of highest-quality γ beams. A 2.5 MeV γ beam with an envisaged intensity of 10 15  photons s −1 , as ultimately envisaged for an ERL-based γ -beam facility, narrow band width (10 −3 ), and extremely low emittance (10 −4  mm 2  mrad 2 ) offers the possibility to produce a high-intensity bright polarized positron beam. Pair production in a face-on irradiated W converter foil (200 μm thick, 10 mm long) would lead to the emission of 2×10 13 (fast) positrons per second, which is four orders of magnitude higher compared to strong radioactive 22 Na sources conventionally used in the laboratory. Using a stack of converter foils and subsequent positron moderation, a high-intensity low-energy beam of moderated positrons can be produced. Two different source setups are presented: a high-brightness positron beam with a diameter as low as 0.2 mm, and a high-intensity beam of 3×10 11 moderated positrons per second. Hence, profiting from an improved moderation efficiency, the envisaged positron intensity would exceed that of present high-intensity positron sources by a factor of 100. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-011-4594-0 Authors C. Hugenschmidt, FRM II and Physik Department E21, Technische Universität München, 85747 Garching, Germany K. Schreckenbach, FRM II and Physik Department E21, Technische Universität München, 85747 Garching, Germany D. Habs, Fakultät für Physik, Ludwig-Maximilians Universität, 85748 Garching, Germany P. G. Thirolf, Fakultät für Physik, Ludwig-Maximilians Universität, 85748 Garching, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    The photoluminescence (PL) of LiTb(PO 3 ) 4 , LiGd 0.97 Sm 0.03 (PO 3 ) 4 , and LiTb 0.97 Sm 0.03 (PO 3 ) 4 under vacuum ultraviolet (VUV)/ultraviolet (UV) excitation were studied. We observed the VUV–UV sensitization of Sm 3+ emission (561 nm, 601 nm, 649 nm, and 710 nm) by Tb 3+ in LiTb(PO 3 ) 4 :Sm 3+ , which leads to the yellow light emission (486 nm, 546 nm, 561 nm, 587 nm, 601 nm, 621 nm, 649 nm, and 710 nm) of LiTb(PO 3 ) 4 :Sm 3+ phosphor under UV and VUV excitation. The emission is a result of partial energy transfer from Tb 3+ to Sm 3+ , which is discussed in detail in terms of the excitation and emission spectra and decay curves. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-011-4580-6 Authors B. Han, KLGHEI of Environment and Energy Chemistry, MOE Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China H. Liang, KLGHEI of Environment and Energy Chemistry, MOE Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China Y. Huang, Beijing Synchrotron Radiation Facilities, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100039 People’s Republic of China Y. Tao, Beijing Synchrotron Radiation Facilities, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100039 People’s Republic of China Q. Su, KLGHEI of Environment and Energy Chemistry, MOE Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    Tricalcium aluminate doped with Eu 3+ was prepared at furnace temperatures as low as 500°C by using the convenient combustion route and examined using powder X-ray diffraction, scanning electron microscope and photoluminescence techniques. A room-temperature photoluminescence study showed that the phosphors can be efficiently excited by UV/Visible region, emitting a red light with a peak wavelength of 616 nm corresponding to the 5 D 0 – 7 F 2 transition of Eu 3+ ions. The phosphor exhibits three thermoluminescence (TL) peaks at 195°C, 325°C and 390°C. Electron Spin Resonance (ESR) studies were carried out to study the defect centres induced in the phosphor by gamma irradiation and also to identify the defect centres responsible for the TL process. Room-temperature ESR spectrum of irradiated phosphor appears to be a superposition of three distinct centres. One of the centres (centre I) with principal g-value 2.0130 is identified as O − ion while centre II with an axially symmetric principal values g ∥ =2.0030 and g ⊥ =2.0072 is assigned to an F + centre (singly ionized oxygen vacancy). O − ion (hole centre) correlates with the TL peak at 195°C and the F + centre (electron centre), which acts as a recombination centre, is also correlated to the 195°C TL peak. F + centre further appears to be related to the high temperature peak at 390°C. Centre III is also assigned to an F + centre and seems to be the recombination centre for the TL peak at 325°C. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-011-4589-x Authors V. Singh, Department of Chemistry, Kyungpook National University, Daegu, 702701 Republic of Korea S. Watanabe, Institute of Physics, University of Sao Paulo, 05508-090 Sao Paulo, SP, Brazil T. K. Gundu Rao, Institute of Physics, University of Sao Paulo, 05508-090 Sao Paulo, SP, Brazil I.-J. Lee, Department of Chemistry, Dongguk University, 707 Suckjang-dong, Gyeongju-Si, Gyeongbuk, 780-714 Korea Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    Nonlinear electron emission processes induced by surface plasmon oscillations have been studied both experimentally and theoretically. The measured above-threshold electron spectra extend up to high energies whose appearance cannot be explained solely by standard non-perturbative methods, which predict photon energy separated discrete energy line spectra with the known fast fall–plateau–cutoff envelope shape, even when taking the large field enhancement into account. The theoretical analysis of our data, based on the concept of plasmon-induced surface near-field effects, gives a reasonably good explanation and qualitative agreement in the whole intensity range. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-011-4582-4 Authors S. Varró, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest, Hungary N. Kroó, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest, Hungary Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    In this study, optical bistability accompanied by spatial hysteresis was demonstrated in an Nd:GdVO 4 laser with an intracavity twisted-nematic liquid crystal. The low branch of power hysteresis mainly has the spatial distribution of the fundamental mode as the pump power increases, whereas a four-mode and varying transverse pattern exist in the high branch of power hysteresis as the pump power decreases. The result revealed that the power and spatial hysteresis is controlled by the director axis reorientation and the order parameter modification in twisted-nematic liquid crystals, which is determined by the non-uniform transverse distribution of the intracavity laser intensity. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-011-4590-4 Authors M.-D. Wei, Department of Electro-Optical Engineering, National Cheng Kung University, No. 1, University Road, Tainan City, 701 Taiwan, R.O.C. D.-Y. Huang, Department of Photonics, Feng Chia University, 100 Wenhwa Rd., Seatwen, Taichung, 407 Taiwan, R.O.C. C.-C. Hsu, Department of Electro-Optical Engineering, National Cheng Kung University, No. 1, University Road, Tainan City, 701 Taiwan, R.O.C. A.-K. Chang, Department of Photonics, Feng Chia University, 100 Wenhwa Rd., Seatwen, Taichung, 407 Taiwan, R.O.C. J.-H. Lin, Department of Electro-Optical Engineering & In Institute of Electro-Optical Engineering, National Taipei University of Technology, Taipei, 10608 Taiwan, R.O.C. Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    A novel technique is represented that allows one to measure vibrations from a distant object with micron and sub-micron amplitudes in real time. The method is based on the speckle interference phenomena and speckle pattern analysis. The scheme allows us to use a single photodiode as a photo-detector and to obtain information from an analog signal without any additional post-processing, which significantly simplifies the device realization compared with the available today laser vibrometers based both on interferometric and on speckle pattern analysis principles. The scheme investigated was implemented as a device and several studies of the practical applications were carried out. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-011-4585-1 Authors A. A. Veber, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia A. Lyashedko, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia E. Sholokhov, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia A. Trikshev, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia A. Kurkov, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia Y. Pyrkov, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia A. E. Veber, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia V. Seregin, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia V. Tsvetkov, General Physics Institute, GSP-1, Vavilov str., 38, Moscow, 119991 Russia Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    An ultrahigh contrast laser pulse of over 10 11 for 6 ps before the main pulse was achieved by employing a double plasma mirror installed at the end of a 100 TW Ti:sapphire laser system. Spatial beam qualities such as focusability and stability were found to be extremely sensitive in the range of 14–360 J/cm 2 on the double plasma mirror, while ultrahigh contrast was maintained. At the fluence of 90 J/cm 2 the focusability of the ultrahigh contrast laser was not degraded, and the stability was very close to that obtained without the double plasma mirror when the 2-dimensional normalized standard deviation and the correlation function for several laser beam profiles were analyzed. These results are requisites for carrying out relativistic laser-plasma interactions with ultrahigh contrast laser pulses, enabling the use of ultrathin solid targets. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-011-4584-2 Authors IJ. Kim, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea I. W. Choi, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea S. K. Lee, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea K. A. Janulewicz, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea J. H. Sung, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea T. J. Yu, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea H. T. Kim, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea H. Yun, Department of Physics, KAIST, Yuseong-gu, Daejeon, 305-701 Korea T. M. Jeong, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea J. Lee, Center for Femto-Atto Science and Technology, Advanced Photonics Research Institute, GIST, Gwangju, 500-712 Korea Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Description:    We describe a high-energy, frequency chirped laser system designed for optical Stark deceleration of cold molecules. This system produces two, pulse amplified beams of up to 700 mJ with flat-top temporal profiles, whose frequency and intensity can be well controlled for durations from 20 ns–10 μs. The two beams are created by amplifying a single, rapidly tunable Nd:YVO 4 microchip type laser at 1064 nm, which can be frequency chirped by up to 1 GHz over the duration of the pulse. Intensity modulation induced by relaxation oscillations in the microchip laser during the frequency chirp are virtually eliminated by injection locking a free running semiconductor diode laser before pulsed amplification. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-011-4599-8 Authors N. Coppendale, University College London, Gower Street, London, WC1E 6BT UK L. Wang, University College London, Gower Street, London, WC1E 6BT UK P. Douglas, University College London, Gower Street, London, WC1E 6BT UK P. F. Barker, University College London, Gower Street, London, WC1E 6BT UK Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171