激光数字波面干涉仪傅里叶变换移相干涉术

讨论了一种新的干涉图处理方法，能实时快速准确地提取干涉图信息，直接测量波面的位相分布，获得较高的位相分辨率和空间分辨率，使光学波面的检测精度达到λ／１００以上，并且实现了波面的的实时显示。     

动态光束波前测量系统

动态光束波前测量系统一、简介本系列设备采用动态哈特曼传感器原理，配合专用波前处理软件包，具有以下特点：●同时测量光束的相位和光强（即复振幅）分布，获得评价激光光束和光学系统质量的全面数据。●测量时与光学基准脱机，环境适应能力强。●连续记录动态变化。●...     

用Hartmann－Shack传感器测量激光束的波前相位

Ｈａｒｔｍａｎｎ－Ｓｈａｃｋ传感器已经用于自适应光学系统。它可以同时探测出一束光的振幅和相位信息。通过一个位置传感器，比如ＣＣＤ，它就可以成为一种对光学系统和光束的静态和动态质量诊断的有力工具。从Ｈ－Ｓ波前传感器的输出（波前斜率和近场强度分布），就可以推算出远场特点，如ＰＳＦ和ＯＴＦ。本文将介绍波前重构的理论分析和远场特征评估。同时也给出了光束质量的静态和动态的测量结果。     

用Hartmann—Shack传感器测量激光束的波前相位

Ｈａｒｔｍａｎｎ－Ｓｈａｃｋ传感器已经用于自适应光学系统。它可以同时探测出一束光的振幅和相位信息。通过一个位置传感器，比如ＣＣＤ，它就可以成为一种对光学系统和光束的静态和动态质量诊断的有力工具。从Ｈ－Ｓ波前传感器的输出（波前斜率和近场强度分布），就可以推算出远场特点，如ＰＳＦ和ＯＦＴ。本文将介绍波前重构的理论分析和远场特征评估。同时也给出了光束质量的静态和动态的测量结果。     

光子计数动态剪切干涉仪的实时波前处理机

介绍了光学计数方法下的波前处理机的构成及工作原理，解决了弱光条件下的光子脉冲计数，并以ＴＭＳ３２０Ｃ２５高速数字信息处理器为核心，快速完成了波前相位计算，波前重构，控制信号的并行输出及波面信息的实时监测。     

纳米计量与分子坐标测量机系统设计（2）

NanmetrologyandMolecularMeasuringMachineSystemDesign（2）WangJia4分子测量机计量系统STM和AFM均不是计量型仪器，而是作为位置传感器。分子坐标测量机必须采用能够溯源的超高分辨率激光外差干涉仪作为测量参考基准，并测量探针和样品之间的相对运动。激光外差可采用塞曼频率分裂，多模激光器或声光电光调制原理。干涉仪采用了光学8倍频。用相位计从时间间隔分析器中计算相位，其时间分辨率为200pa，电子细分技术实现1000细分。干涉仪的分辨率为0．075um。获得高精度的主要障碍是激光器和干涉仪光学元件中偏振态混合效应和非线性…     

一种新的外差干涉信号处理方法—相位及相位整数测量法

介绍了一种新的外差干涉信号处理方法－相位及相位整数测量法。用此方法不仅可使干涉测量的分辨率提高到λ／１０００－λ／２０００，而且扩大了测量范围，解决了大范围、动态测量位移的问题。文中还给出了用此方法进行信号处理的外差干涉仪测量压电陶瓷动态位移的实验结果。     

剪切干涉仪光子计数法动态波前探测

实时动态波前探测技术是自适应光学系统最重要的单元技术之一。本文报导了在弱光条件下,利用动态剪切干涉仪和光子计数法进行弱光波前误差探测的实验。叙述了波前探测装置的原理,讨论了相位测量的主要误差源。实验结果表明,在每一探测周期内,仅有几十到一百个光电子脉冲的情况下,可获得波前信息。     

液晶空间光调制器相位调制特性研究

研究了美国BNS公司生产的Modal P256反射型电寻址液晶空间光调制器的相位调制特性和时间响应特性.采用He-Ne激光作光源,建立迈克尔孙干涉光路观察波前相位变化,给出器件的相位调制特性曲线.分析测量了器件的相位响应不一致性和像素间的相位交连.通过测量液晶器件对方波和正弦控制信号的相位响应延迟,分析了液晶空间光调制器(LC-SLM)的时间响应特性.理论分析与实验结果说明:在特定的入射偏振条件下,LC-SLM实现纯相位调制,可用作高分辨力波前校正器件,然而极慢的响应速度和极低的时间带宽限制了它在动态变化波前相差校正中的应用.     

用于大口径非球面的波前功率谱密度检测

光学元件加工质量的检测和评价工作是保证整个光学系统安全、正常运行的关键。在总结非球面常用检验指标优、缺点的基础上,讨论了测量大口径非球面的波前功率谱密度时的系统组成、工作原理和软件设计的总体思路。为了减少系统误差的影响,求解波前功率谱密度时,通过引入系统传递函数校正测量值来实现。使用大口径相位干涉仪作为波前检测仪器,证实波前功率谱密度能定量给出波前畸变的空间频率分布,并用于作为大口径光学元件质量的评价标准。给出一个测试口径为64mm×64mm光学元件测试结果,有效频率为0.03mm-1～3.87mm-1,rms为0.0064λ。     

帧频2900Hz的高速实时波前处理机

波前处理机是自适应光学系统波前处理运算的中心 ,其运算延时直接影响系统的控制带宽。在 6 1单元自适应光学系统中 ,我们根据采样频率 2 90 0 Hz的Hartmann波前传感器输出信号的特点 ,采用流水和并行处理技术 ,用 1 2片TMS32 0 C5 0和 5片 TMS32 0 C31处理器 ,研制了我国首台峰值运算速度达 8.5亿次/秒的专用高速实时数字波前处理机 ,满足了系统的实时性要求。     

自适应光学系统时间带宽和空间带宽的匹配

自适应光学系统存在的时间带宽和空间带宽。为了有效地利用自适应光学系统的系统资源，必须使这两种带宽匹配。本文通过经系统校正后的剩余波前扰动相位的均方差与系统时间带宽和空间带宽的关系，研究了在不同条件下系统时间带宽和空间带宽的匹配问题。     

Aberration compensation of holographic particle images using digital holographic microscopy

Characterisation of small and large-scale vortices in turbulent flows demands a system with high spatial resolution. The measurement of high spatial resolution, three-dimensional vector displacements in fluid mechanics using holography, is usually hampered by aberration. Aberration poses some problems in particle image identification due to low fidelity of real image reconstruction. Phase mismatch between the recording and the reconstruction waves was identified as the main source of aberration in this study. This paper demonstrates how aberration compensation can be achieved by cross-correlating the complex amplitude of an aberrated reconstructed object with the phase conjugate of a known reference object in the plane of the hologram (frequency space). Results favourably show significant increase in Strehl ratio and suppression of background noise that are more pronounced for particle images of 10 and 5 microns. It is clear from the work conducted that wavefront aberration measurement and compensation of holographic microscopic objects are now possible with the use of a variant digital holographic microscope.     

基于脉动阵列的自适应光学实时波前处理机设计

针对自适应光学系统对波前处理机高计算量、高实时性的要求,本文提出了一种基于脉动阵列的自适应光学实时波前处理方法.该方法将脉动阵列的概念引入波前处理机设计,完成了波前斜率计算、复原运算和控制运算向脉动阵列的映射,合理地建立了数据的深度流水线,同时分析了以FPGA技术实现时系统的计算延时.对于48个子孔径,61单元的自适应光学系统,以一片Xilinx Virex-Ⅱ XC2V3000芯片实现了基于脉动阵列的实时波前处理机,实验测得计算延时仅8.6μs,结果表明该方法能极大地提高系统的实时性,集成度、通用性和扩展性.     

Effect of aberrations and scatter on image resolution assessed by adaptive optics retinal section imaging

The effect of increased high-order wavefront aberrations on image resolution was investigated, and the performance of adaptive optics (AO) for correcting wavefront error in the presence of increased light scatter was assessed in a model eye. An AO section imaging system provided an oblique view of a model retina and incorporated a wavefront sensor and deformable mirror for measurement and compensation of wavefront aberrations. Image resolution was quantified by the width of a Lorentzian curve fitted to a laser line image. Wavefront aberrations were significantly reduced with AO, resulting in improvement of image resolution. In the model eye, image resolution was degraded with increased high-order wavefront aberrations (horizontal coma and spherical) and improved with AO correction of wavefront error in the presence of increased light scatter. The findings of the current study suggest that AO imaging systems can potentially improve image resolution in aging eyes with increased aberrations and scatter.     

High-resolution retinal imaging with micro adaptive optics system

Based on the dynamic characteristics of human eye aberration, a microadaptive optics retina imaging system set is established for real-time wavefront measurement and correction. This paper analyzes the working principles of a 127-unit Hartmann-Shack wavefront sensor and a 37-channel micromachine membrane deformable mirror adopted in the system. The proposed system achieves wavefront reconstruction through the adaptive centroid detection method and the mode reconstruction algorithm of Zernike polynomials, so that human eye aberration can be measured accurately. Meanwhile, according to the adaptive optics aberration correction control model, a closed-loop iterative aberration correction algorithm based on Smith control is presented to realize efficient and real-time correction of human eye aberration with different characteristics, and characteristics of the time domain of the system are also optimized. According to the experiment results tested on a USAF 1951 standard resolution target and a living human retina (subject ZHY), the resolution of the system can reach 3.6?LP/mm, and the human eye wavefront aberration of 0.728λ (λ=785?nm) can be corrected to 0.081λ in root mean square (RMS) so as to achieve the diffraction limit (Strehl ratio is 0.866), then high-resolution retina images are obtained.     

流体物理研究所的高速光学技术

本文阐述了高速摄影技术、光谱测温、激光干涉测速和脉冲 X射线摄影的实时光电记录等光学测试技术在中物院流体物理研究所的发展和应用现状。被研究的测试对象均是瞬时高速过程 ,具有时空分辨的要求 ,其时间分辨本领在 ms至 ns范围内     

Shack-Hartmann wavefront sensing with elongated sodium laser beacons: centroiding versus matched filtering

We describe modeling and simulation results for the Thirty Meter Telescope on the degradation of sodium laser guide star Shack-Hartmann wavefront sensor measurement accuracy that will occur due to the spatial structure and temporal variations of the mesospheric sodium layer. By using a contiguous set of lidar measurements of the sodium profile, the performance of a standard centroid and of a more refined noise-optimal matched filter spot position estimation algorithm is analyzed and compared for a nominal mean signal level equal to 1000 photodetected electrons per subaperture per integration time, as a function of subaperture to laser launch telescope distance and CCD pixel readout noise. Both algorithms are compared in terms of their rms spot position estimation error due to noise, their associated wavefront error when implemented on the Thirty Meter Telescope facility adaptive optics system, their linear dynamic range, and their bias when detuned from the current sodium profile.     

Adaptive optics in microscopy

The imaging properties of optical microscopes are often compromised by aberrations that reduce image resolution and contrast. Adaptive optics technology has been employed in various systems to correct these aberrations and restore performance. This has required various departures from the traditional adaptive optics schemes that are used in astronomy. This review discusses the sources of aberrations, their effects and their correction with adaptive optics, particularly in confocal and two-photon microscopes. Different methods of wavefront sensing, indirect aberration measurement and aberration correction devices are discussed. Applications of adaptive optics in the related areas of optical data storage, optical tweezers and micro/nanofabrication are also reviewed.