一种基于光三角法的激光测振仪

介绍了一种基于光三角法的激光非接触测振仪,对激光测振仪的结构参数的优化设计进行了分析。研制的激光测振仪的主要技术参数为工作距离 ４０ｍ ｍ ～２ｍ ,测量范围 ２～５０ｍ ｍ ,测量分辨力 ２～２０μｍ ,频率响应 ０～３ｋ Ｈｚ。     

Optical Angular Encoder Installation Error Measurement and Calibration by Ring Laser Gyroscope

This paper deals with the installation errors of an optical angular encoder (OAE). A harmonic model is proposed to describe the installation errors, including the effects of eccentricity, swash, and distortion. Moreover, a method of OAE calibration with the ring laser gyroscope (RLG) is introduced. The calibration method can potentially reach the accuracy of 0.1$^{primeprime}$. The calibration method is proved to be experimentally effective. With the harmonic model obtained from the experiment, the calibration of the OAE can be carried out in real time.      

基于飞秒激光器光学频率梳的绝对距离测量

提出使用飞秒激光器的光学频率梳测量绝对距离的方法.将一个飞秒激光器作为绝对距离测量的光源,搭建迈克尔逊干涉结构,利用色散干涉原理进行相应的光谱分析,得到干涉光路的光学路径差引起的相位差,最终计算出干涉光路的光学路径差.实验结果表明我们的长度测量方法精确度高,分辨力达到纳米量级.最小测量距离达到9 μm,非模糊范围达到5...     

用数字波面干涉仪快速检测平晶的平行度

文章提出了一种新的检测方法即用数字波面干涉仪检测平晶的平行度.分析了测量不确定度的来源,并对测量不确定度进行了分析评定.与传统的方法相比在保证测量准确度的前提下,大大提高了工作效率.     

Measurement of Intraocular Optical Distances Using Partially Coherent Laser Light

Abstract

The application of partially coherent laser light to measure intraocular optical distances is discussed. In a first step the optical thickness of the retina at the macula and the optical length of the eye has been measured and a precision of ± 0·03 mm has been obtained. The results of a comparison with the acoustically determined eye length and first fundus profile measurements are presented.     

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.     

Direct Measurement of Rotation by a Laser Speckle Method

The laser speckle pattern produced by the coherent illumination of a small circular portion of a doubly exposed photograph contains enough information to reveal not only the displacement but also the rotation of a rigidly moving two-dimensional field. The displacement of the field is contained in the resulting parallel speckle fringe spacing in the usual way. The magnitude of the rotation of the field, however, may be determined by measuring the radius of the circular region within which these displacement speckle fringes appear. Photographs and analyses of the resulting speckle patterns are presented. Non-rigid two-dimensional motion and its relation to incompressible fluid flow is also discussed.     

一种基于光拍频的连续激光调制光谱测量方法

针对F-P干涉仪分析连续激光调制光谱的局限性,本文提出了一种基于光拍频的连续激光调制光谱的测量方法,该方法可实现调制频率低达千赫兹的连续激光调制光谱的测量.本方法以光电转换理论为基础,利用频谱分析仪测得参考光与连续调制光谱的拍频信号,然后通过相应的数学计算得到连续调制光谱的各个光频的相对电场强度,从而实现连续调制光谱的分析.本文在理论建模与分析的基础上,利用该方法对半导体激光器出射激光经电光调制器调制产生的调制光谱进行了测量,测量结果与F-P干涉仪测量结果一致,验证了该方法的可行性.     

用于人脸识别的非相干光形态学处理器

设计了一个用于人脸图像光学识别处理的非相干光形态学处理器。系统中采用互补编码击中击不中变换以改善传统光学相关器的性能。基于该方法，构建了一个紧凑性的人脸光学识别非相干光系统，图象库中存有96幅人脸图象，可以达到每秒钟10幅的识别速度，识别正确率大于90％，对于8°以内的旋转畸变、30％以内的Gauss噪声干扰以及50％以内的图像缺损具有相当好的容错能力。     

Optical Frequency Metrology of an Iodine-Stabilized He-Ne Laser Using the Frequency Comb of a Quantum-Interference-Stabilized Mode-Locked Laser

We perform optical frequency metrology of an iodine-stabilized He-Ne laser using a mode-locked Ti:sapphire laser frequency comb that is stabilized using quantum interference of photocurrents in a semiconductor. Using this technique, we demonstrate carrier-envelope offset frequency fluctuations of less than 5 mHz using a 1 s gate time. With the resulting stable frequency comb, we measure the optical frequency of the iodine transition [¹²⁷I₂ R(127) 11-5 i component] to be 473 612 214 712.96 ± 0.66 kHz, well within the uncertainty of the CIPM recommended value. The stability of the quantum interference technique is high enough such that it does not limit the measurements.     

Absolute Measurement of Thermophysical and Optical Thin-Film Properties by Photothermal Methods for the Investigation of Laser Damage

Perspectives and limits of the application of the photothermal technique are given for the measurement of absorption, thermal, and thermoelastic properties in thin films. The peculiarities of this technique in the frequency and time domains are discussed in some detail, and selected important results with respect to laser damage studies in optical coatings are pointed out. Emphasis is placed on the absolute measurement of both optical and thermophysical properties in dielectric materials in thin-film form and, also, on the influence of both absorption and changed thermal properties in thin films on their thermally induced laser damage resistance.     

New Method for Optical Pumping of a Solid State Laser through the Use of Light Fibres

The present work is concerned with the theoretical design and investigation of a new system for optical pumping of solid state lasers. The originality of the new system lies in the use of optical fibres to transmit the light from its source to the laser-active material, thus allowing complete spatial separation of the two. The degree of uniformity achieved in illuminating the surface of the laser material is theoretically investigated and is shown to be very high. The efficiency of the system is also examined and the resulting advantages and disadvantages are pointed out. The possibilities for the realization of such a system are discussed and various ways of construction are proposed.     

压力变送器的测量不确定的评定

文章介绍了压力变送器测量不确定度评定,给出结果。     

光学互相关测速在声发射测粒中的应用

声发射测粒方法是通过测量分析粉体颗粒碰撞某个平面产生的声发射信号脉冲波形来荻取粒径分布信息的,为了获知颗粒的碰撞速度和粉体材料的声学参数,本文中尝试将光学互相关测速与声发射测量相结合,设计了同时测量自由落体颗粒碰撞平板的瞬时速度和声发射信号脉宽的实验。初步实验结果表明:光学互相关测速可以为声发射信号分析提供必要的信息。     

激光测速靶结构优化的光路分析

目的 研究正方形有效靶区位于靶框中央的激光测速靶结构的可行性。方法 分别对采有单圆弧柱面反射镜和双圆弧柱面反射镜方案进行光路分析，确定各主要参数，并通过共轭光学系统的像差分析来验证其合理性。结果 两种模型都能满足方形有效靶区与靶框几何相似且位于靶框中央。结论 经实验论证，单圆弧柱面反射镜方案和双圆弧柱面反射镜方案都是可行的,为设计大口径弹丸用激光测速靶提供了可靠的依据。     

Drift of an Optical Fibre Gyroscope Caused by the Faraday Effect and Its Reduction by Use of a Polarizing Fibre

The drift of fibre gyroscopes caused by a magnetic field via the Faraday effect is formulated in a simple model with a polarizing fibre as a sensing loop. It is found that polarizing fibre, which has a extremely large loss difference between two polarization modes, can make the drift less than that with polarization-maintaining fibre. In this case, the drift is inversely proportional to the square of the loss difference. Although currently available polarizing fibre must be improved to have a larger loss difference, by using such a polarizing fibre or an absolute single-polarization fibre, we can reduce the requirement for shielding the magnetic field and/or the way of winding the sensing loop. The use of these fibres is attractive for applications that demand ultra-low drift, for example, geophysical applications.     

Measurement of Material Anisotropy by Dual-Probe Laser Interferometer

Abstract

A novel dual-probe laser interferometer, which has the advantage that it measures the surface displacements of the same surface wave at two locations, has been used to measure the speeds of surface waves and pseudo-surface waves on a silicon single crystal. Two configurations have been investigated. When the distance between the two points of detection is large relative to the length of the acoustic wave, the two signals detected by the probes are separated in the time domain. Hence the signal travel time can be found by the autocorrelation method. When the distance between the two points of detection is short relative to the acoustic wave, a composite signal is obtained consisting of two overlapping signals. Then the power cepstrum method is employed to extract the signal travel time between the probe points. The speeds for both types of surface waves are shown as functions of direction relative to the [001] crystal axis. The results have been compared with theoretical calculations and line-focus acoustic microscopy measurements.     

激光测振技术的最新进展

激光测振技术在近20年取得了巨大进展。本文以2004年6月在意大利召开的第六届激光测振国际会议的技术内容为基础，重点介绍激光测振技术在计量学方面的进展和在其他领域的应用。     

Demonstration of an Optical Isolator with a Semiconductor Guiding Layer that was Obtained by Use of a Nonreciprocal Phase Shift

We present the experimental study of an optical isolator with a semiconductor guiding layer that was obtained by use of a nonreciprocal phase shift. The isolator is equipped with an optical interferometer composed of tapered couplers, nonreciprocal phase shifters, and a reciprocal phase shifter. The nonreciprocal phase shifter was constructed by wafer direct bonding between the semiconductor guiding layer and the magneto-optic cladding layer. The isolator, designed for the 1.55-mum wavelength, was fabricated to investigate the characteristics of each component. By applying an external magnetic field to the nonreciprocal phase shifter, we achieved an isolation ratio of approximately 4.9 dB in the interferometric isolator.