Measurement Problems in Optical Monitoring Systems

A probabilistic image model is proposed. According to the model, the noise of the boundaries has the principal effect on the precision with which the dimensions of optical monitoring objects are measured. Results of theoretical and experimental investigations of measurement precision are presented. An approach to the determination of monitoring reliability and the selection of the resolution of a machine vision system based on structural requirements is formulated.     

成像光学工程面临的光学问题

文章简单论述了现代成像光学主要领域的情况,指出非球面反射系统是发展的必然趋势。讨论了加工与检验方面的基本情况及应着重深入研究的问题。对镜坯材料也提了一点看法。     

大面积激光测速靶光学系统的设计与分析

提出了以微珠玻璃原向反射屏和光纤光锥构建大面积激光测速靶的新方案,对微珠玻璃原向反射屏的反射率和原向反射光斑的光强分布进行了测试分析,并以此作为光学系统设计的依据.实验结果表明:光学系统设计合理,完全可用于各种弹丸初速的实际测量.     

Channel Modeling and Target Design for Two-Dimensional Optical Storage Systems

In this paper, we first show that the symbol response of the two-dimensional (2-D) optical storage (TwoDOS) channel can be computed by a one-dimensional (1-D) Hankel transform, instead of the 2-D Fourier transform. This results in a computationally efficient approach for generating readback signals in the presence of pit-size variations. We also show how to design a 2-D minimum mean-square error (MMSE) equalizer for channels with these distortions. Second, we present a novel way to jointly design equalizer and target under linear constraints on the target, by transforming the 2-D target design problem into a 1-D form. Using a 2-D Viterbi detector, we investigated different target constraints. The results show that the newly proposed “2-D monic constraint” is a reasonable target constraint for a TwoDOS system.     

Optical Communication Systems

Thermal lensing of the active medium inside a laser resonator leads to a dependence of the beam divergence on the optical pumping power. Two effects influence the multimode divergence: the fundamental mode divergence θ ₀ and the mode order m. By using a suitable resonator set-up the variations of the two quantities with pumping power can be arranged to offset each other so that the resultant beam divergence remains constant. When the condition for insensitivity is derived the resulting constant divergence is found to be θ _ma = R/d _i, where R is the radius of the limiting aperture of the active medium, and d _i is the distance from the mirror S_i to the principal plane of the active medium. Experiments with Nd-YAG/glass lasers have confirmed these theoretical results.     

两探测面结构激光粒度仪的接收光路设计

为了扩大激光粒度仪测量的动态范围,采用同轴的两组接收透镜,将两个硅光电探测器阵列分别置于前组透镜的后焦面和两组透镜的组合后焦面上,对测量信号进行组合后用改进共轭梯度法处理数据。通过优化光路结构,采用两组双胶合透镜和探测环半径均不大于45mm的探测器可满足同时测量5～3500μm粒径的要求。     

The Design of Optical Systems with Extended Depth of Focus

The SLAMS Version 14 optimization programme was modified to include geometrical MTF values, in two defocused image planes, in the merit function. This programme was successfully used in the design of lenses for office copying machines. In such cases, a major effort is made to extend the focal depth maintaining a given MTF value. Conventional methods which minimize the aberrations in a single image plane may be less adequate under those circumstances.     

飞秒激光及光钟

结合飞秒激光超强、超快、超稳、宽频、广谱、相干的特点,介绍了其相应的技术应用情况:应用超快特性的微观物理、生物、化学、信息、通信等;以超强应用为对象的材料加工、制备、电子对撞加速器、受控核聚变等;以超稳特性应用为对象的光频测量、长距离测量、光钟等,并简介了光钟。     

Optical Systems with Feedback

Some aspects of feedback technique in optical systems are examined. The eigenfunctions suitable for describing systems where both space and frequency limitations occur are discussed. Applications to the generation of super-resolving pupils and to the band unlimited restoration of images are presented.