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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

Fully phase color image encryption based on joint fractional Fourier transform correlator and phase retrieval algorithm

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Chinese Optics Letters 2011年第2期9卷 30-32页

作者：鲁丁金伟民 Institute of Information Optics Zhejiang Normal University

A novel fully phase color image encryption/decryption scheme based on joint fractional Fourier transform correlator （JFRTC） and phase retrieval algorithm （PRA） is proposed. The security of the system is enhanced by the fractional order as a new added key. This method takes full advantage of the parallel processing features of the optical system and could optically realize single-channel color image encryption. The system and operation procedures are simplified. The simulation results of a color image indicate that the new method provides effcient solutions with a strong sense of security.

关键词： Algorithms Color Cryptography optical systems

Experimental investigation on wake profile detection based on laser scattering by bubbles

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Chinese Optics Letters 2007年第10期5卷 609-612页

作者：苏丽萍赵卫疆胡孝勇任德明刘西站 Institute of Opto-Electronics Harbin Institute of Technology

The optical system for detecting wake profiles based on laser backscattering by bubbles at 180° is reported, in which the monostatic optical geometry is adopted and the power density estimation is used to process bubble scattering signal. The profiles of wakes produced by a two-blade propeller with a diameter of 46 mm at 6000 and 8000 rpm are measured using this system. It is shown that the wake region can be identified, the wake with different shapes can be distinguished, and the fine structure within wakes can be detected. Also, the repeatability of the results is tested experimentally. Results show the feasibility of this system in wake profile detection.

关键词： Backscattering Bubbles (in fluids) Laser beams optical systems Propellers

Generation and application of the twisted beam with orbital angular momentum

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Chinese Optics Letters 2007年第2期5卷 89-92页

作者：高明伟高春清林志锋 Department of Opto-Electronics Engineering Beijing Institute of TechnologyBeijing 100081

The twisted Laguerre-Gaussian beam was generated by transforming of Hermite-Gaussian beams through an optical system consisting of three rotated cylindrical lenses. The intensity distribution and phase structure of the twisted hollow beam were theoretically analyzed by using Collins diffraction integral. By utilizing the method of mode decomposition, the theory of transformation was analyzed. In the experiment, micro particles were trapped and rotated by this twisted beam.

关键词： Angular momentum optical systems Phase structure

An Exact Solution and the Pancharatnam Phase for the Generalized Two—Mode optical System

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Chinese Physics Letters 2002年第4期19卷 463-465页

作者：侯邦品王顺金等 InstituteofModernPhysics SouthwestJiaotongUniversityChengdu610031

Using the algebraic dynamical method, we obtain the exact solution for the generalized two-mode optical system. From the solution, the Pancharatnam phase and the mean values of the number operators of the system are c... 详细信息

关键词： optical systems

Pupil design based on Fisher information optimization to extend field depth in practical optical system

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Chinese Optics Letters 2010年第2期8卷 159-161页

作者：刘钦晓赵廷玉陈燕平张文字余飞鸿 State Key Laboratory of Modern optical Instrumentation Optical Engineering DepartmentZhejiang University Physics Department College of ScienceNingbo University of Technology

Wavefront coding （WFC） is used to extend the field depth of an incoherent optical system by employing a phase mask on the pupil. We uses a Fisher information （FI） metric based optimization method to design a phase mask by taking the modulation transfer function （MTF） of the practical optical system into consid- eration. This method can modulate the wavefront so that the point spread function and optical transfer function are insensitive to the object distance. The simulation results show that the optimized phase mask based on the proposed method can further improve the defocusing image quality while maintaining the focusing image quality.

关键词： Fisher information matrix Image quality optical design optical systems optical transfer function Optimization Wavefronts

Localized CO_2 laser treatment and post-heating process to reduce the growth coef f icient of fused silica surface damage

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Chinese Optics Letters 2011年第6期9卷 73-75页

作者：徐世珍祖小涛袁晓东 School of Physical Electronics University of Electronic Science and Technology of China Research Center of Laser Fusion China Academy of Engineering Physics

The lifetime of optical components in high-fluence ultraviolet （UV） laser applications is typically limited by laser-initiated damage and its subsequent growth. Using 10.6-μ m CO 2 laser pulses, we successfully mitigate 355-nm laser induced damage sites on fused silica surface with dimensions less than 200 μ m. The damage threshold increases and the damage growth mitigates. However, the growth coefficients of new damage on the CO 2 laser processed area are higher than those of the original sample. The damage grows with crack propagation for residual stress after CO 2 laser irradiation. Furthermore, post-heating is beneficial to the release of residual stress and slows down the damage growth.

关键词： Carbon dioxide Heating Laser applications optical systems Residual stresses

Measurement of spatial object's exterior attitude based on linear CCD

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Chinese Optics Letters 2008年第7期6卷 505-509页

作者：艾莉莉袁峰丁振良 Department of Automatic Testing and Control Harbin Institute of TechnologyHarbin 150001

It is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy. The subsystem for three-dimensional （3D） coordinate reconstruction of point target （S3DCRPT） which is composed of three one-dimensional （1D） cameras based on linear charge-coupled device （CCD） can determine the distant light spots＇ spatial position. The attitude angle of the measured object is determined by the spatial solution while the coordinate reconstruction is separately carried on by the S3DCRPT with some point cooperation targets （PCTs） on the measured object. A new optical system is designed to solve the interference problem with one-to-one relationship between the PCTs and the S3DCRPT optical subsystems, which improves the measurement accuracy and saves space. The mathematical model of the attitude measurement is established, and partial and global calibrations are realized for the multi-camera attitude measurement system. The test results show the feasibility of the exterior attitude measurement based on linear CCD.

关键词： Cameras Charge coupled devices Computer networks Digital cameras Ketones Mathematical models optical systems Real time systems Restoration Time measurement

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

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Chinese Optics Letters 2008年第1期6卷 1-4页

作者：丁学科荣健白宏王秀申金娥李芳 School of Physical Electronic University of Electronic Science and Technology of China

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.

关键词： Adaptive optics Computer simulation Mirrors optical systems