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Focusing contribution of individual pinholes of a photon sieve:dependence on the order of local ring of underlying traditional Fresnel zone plate

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Chinese Optics Letters 2010年第3期8卷 256-258页

作者：张军勇曹清卢兴强林尊琪 Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences Department of Physics Shanghai University Department of PhysicsShanghai University

A photon sieve can be composed of a large number of circular pinholes. Each circular pinhole has a contribution to the focusing. For the case of point-to-point imaging, the focusing contribution of an individual circular pinhole can be analytically given. We investigate the dependence of the focusing contribution on the order m of local ring of underlying traditional Fresnel zone plate. In particular, we find that the focusing contribution is simply inversely proportional to the order m. We also present an intuitive explanation. These results are helpful for better understanding of the focusing property of photon sieves.

关键词： optical instruments Photons Sieves

Analysis of speckle reduction based on theory of optical eigenfunction

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Chinese Optics Letters 2011年第3期9卷 48-50页

作者：李高明刘守邱怡申李晖黄艳王丽娟 School of Physics and Mechanical and Electrical Engineering Xiamen University Key Laboratory of Optoelectronic Science and Technology for Medicine Ministry of EducationFujian Provincial Key Laboratory for Photonics TechnologyFujian Normal University

The principle of optical eigenfunction is used in the analysis of speckle reduction in laser projection *** the moving diffiuser is used in the speckle reduction approach,the speckle contrast is decided by both the degree of freedom （DOF） of the projector and the area of resolving cell of the eyes on the *** can gain high DOF of the projector by increasing the space-bandwidth product,i.e.,adopting a projection lens with a high numerical aperture or a large viewing *** best scheme is equalizing the DOF of the scattering wave from a moving diffiuser to that of the projection *** experimental results are in accordance with the conclusion drawn by optical eigenfunction.

关键词： Bandwidth optical instruments optical projectors Speckle

A new circulating two-cell structure for stimulated Brillouin scattering phase conjugation mirrors with 1-J load and 10-Hz repetition rate

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Chinese Optics Letters 2010年第11期8卷 1064-1066页

作者：王雨雷吕志伟郭琦武鹏郑振兴何伟明 National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology

A new approach to realize high-energy and high-power stimulated Brillouin scattering phase conjugation mirrors （SBS-PCMs） is *** reflectivity of SBS-PCM is investigated under a 10-Hz repetition rate and a high energy *** relationship between reflectivity and input energy is examined experimentally with different PCM structures,focus lengths,and medium cell structures.A medium cell with a circulating structure is designed,and its advantage is demonstrated through an experimental comparison with traditional PCM *** 30-cm focus lens and 150-cm collimation lens are optimized when the input energy reaches 1010 mJ at 10-Hz repetition ***,a reflectivity of 84.7% and a higher energy load using the circulating two-cell structure are achieved.

关键词： Dynamic loads High energy physics Lenses Light polarization Mirrors optical instruments optical phase conjugation Reflection Ultrasonics

Analysis and compensation of thermal lens effects in Tm:YAP lasers

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Chinese Optics Letters 2010年第10期8卷 996-999页

作者：姚宝权田义王维李纲王月珠 National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology

The thermal lens effects in Tm：YAP laser are analyzed by solving the Poisson equation with finite difference method. The thermal focal lengths measured are in the range of 40-90 mm at the pump power of 16-34 W, consistent with the simulation results. The temperature contribution coefficient （the linear coefficient between the maximum temperature in the laser crystal and the pump power） of 1.19 K/W is also obtained. The convex lens and plano-concave mirror thermal lens compensation methods are proposed and applied to a high power pumped Tm：YAP laser.

关键词： Lenses Mirrors optical instruments Poisson equation Pumps

Monte-Carlo simulation of effective stiffness of time-sharing optical tweezers

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Chinese Optics Letters 2010年第2期8卷 170-172页

作者：任煜轩吴建光钟敏成李银妹 Hefei National Laboratory for Physical Sciences at the Microscale Department of Physics University of Science and Technology of China Anhui Key Laboratory for Optoelectronic Science and Technology University of Science and Technology of China

The Brownian motion of a polystyrene bead trapped in a time-sharing optical tweezers （TSOT） is numerically simulated by adopting Monte-Carlo technique. By analyzing the Brownian motion signal, the effective stiffness of a TSOT is acquired at different switching frequencies. Simulation results confirm that for a specific laser power and duty ratio, the effective stiffness varies with the frequency at low frequency range, while at high frequency range it keeps constant. Our results reveal that the switching frequency can be used to control the stability of time-sharing optical tweezers in a range.

关键词： Brownian movement Electric power supplies to apparatus Interference suppression optical instruments Polystyrenes Stiffness Switching frequency

Experimental implementation of an all-optical OFDM system based on time lenses

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Chinese Optics Letters 2010年第3期8卷 275-277页

作者：李源李蔚杨克成乔耀军梅君瑶张欢 Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and Technology Key Laboratory of Information Photonics and optical CommunicationsMinistry of Education Beijing University of Posts and Telecommunications

Experimental implementations of continuous optical time domain Fourier transformation based on time lenses and optical orthogonal frequency-division multiplexing （OFDM） system are carried out. Such a system is verified through 100-kin transmission of 10-Gb/s non-return-to-zero （NRZ） intensity-modulated direct-detection （IM-DD） without any dispersion compensation. The system＇s bit error rate （BER） and power penalty are 10 12 and 4 dBm, respectively.

关键词： Fourier analysis Lenses optical communication optical instruments Orthogonal frequency division multiplexing Orthogonal functions Telecommunication systems

Simulation and optimization of spatial light modulation of twisted-nematic liquid crystal display

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Chinese Optics Letters 2010年第10期8卷 960-963页

作者：马百恒姚保利严绍辉彭飞闵俊伟雷铭叶彤 State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Graduate University of the Chinese Academy of Sciences

The approaches to obtaining desired intensity or phase modulation by twisted-nematic liquid crystal display （TN-LCD） have been extensively studied based on the knowledge of the LCD＇s internal structure parameters. Generally, the TN-LCD placed between two linear polarizers （P） produces coupled intensity and phase modulation. To obtain the commonly used phase-only modulation, quarter wave plates （QWPs） are often used in front of and/or behind the LCD. Here we present a method to optimize the optical modulation properties of the TN-LCD to obtain phase-only modulation in the configuration of P-QWP-LCD-QWP-P each with proper orientation. Our method is based on the macroscopical Jones matrix descriptions for the LCD, the QWPs, and the linear polarizers. Through Jones matrix calculations, the orientations of the polarizers and QWPs can be optimized to satisfy differently desired modulation demands. In contrast to the traditional method, which requires knowledge of the LCD＇s internal structure parameters, our method simplified the complicated theory analysis and can work in the absence of information on the LCD＇s internal structure parameters, which are usually not available for the commercial products.

关键词： Crystal structure Light modulation Liquid crystals Liquids Nematic liquid crystals optical instruments optical properties Optimization Phase modulation

A Feasible Approach to optical-Electrical Hybrid Data Storage Using Phase Change Material

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Chinese Physics Letters 2008年第8期25卷 2915-2917页

作者：孙华军侯立松吴谊群翟风潇 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

We present our experimental results supporting optical-electrical hybrid data storage by optical recording and electrical reading using Ge2Sb2Te5as recording medium. The sheet resistance of laser-irradiated Ge2Sb2 Te5 films exhibits an abrupt change of four orders of magnitude （from 107 to 10^3 Ω/sq） with increasing laser power, current-voltage curves of the amorphous area and the laser-crystallized dots, measured by a conductive atomic force microscope （C-AFM）, show that their resistivities are 2. 725 and 3.375 × 10^-3 Ω, respectively, the surface current distribution in the films also shows high and low resistance states. All these results suggest that the laser-recorded bit can be read electrically by measuring the change of electrical resistivity, thus making opticalelectrical hybrid data storage possible.

关键词： LASERS optical instruments SCIENTIFIC apparatus & instruments CURVES

Experiments and analyses of a new type optical system for computed radiography

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Chinese Optics Letters 2010年第8期8卷 800-803页

作者：郑猛冯其波高瞻邵双运丁克勤 School of Science Beijing Jiaotong University China Special Equipment Inspection and Research Center

A new high-performance laser scanning system is designed. In this system, a scanning arm consisting of a pentagonal prism and a scanning object lens is used to replace the traditional Fθ lens, and a circular imaging plate transmission mechanism is specially designed in order to meet the requirement of the scanning arm. At the same time, the stimulation fluorescence can be obtained by the scanning arm. Some main factors that influence the spatial resolution and the performance of the laser scanner system are analyzed, and the analysis results are presented, which is helpful for further optimization design of the system. Experimental results indicate that the images obtained by the system have good visual effects and can meet the requirements of industrial inspection.

关键词： Laser applications Lenses optical instruments optical systems Radiology