Modeling of micro cat's eye retroreflectors using a matrix-based three-dimensional ray tracing technique

In this paper we develop a three-dimensional (3D) ray tracing tool based on the ABCD ray transfer matrices. With symmetric optical components and under paraxial approximation, two sets of 2×2 ABCD matrices, each for a two-dimensional subspace, can be used to describe the 3D ray propagation completely. Compared to commercial ray-tracing software packages, our tool requires no tedious drawing, and the results for various conditions, such as different device dimensions and incident angles, can be easily obtained by simply changing the parameter values used for the calculation. We have employed this matrix-based 3D ray tracing tool to model cat's eye retroreflectors. The cat's eye performance, including the retroreflection efficiency, acceptance angle (i.e., field of view), and beam divergence and deviation, is fully studied. The application of this 3D ray tracing technique can be further extended to other optical components.     

子孔径拼接检验法中倾斜的影响及消除方法

在子孔径拼接检测大口径光学平面时,子孔径检测的数据往往存在倾斜,它将会导致拼接的数据沿着一个方向的倾斜累加,最后引入很大的倾斜误差。由于这种倾斜误差难以手动修正,通过实验,先用最小二乘法编制软件对所测子孔径数据进行消除倾斜处理,然后把去倾斜的子孔径数据进行拼接处理,对比消除倾斜的子孔径拼接结果与全口径直接检测结果,证明了去倾斜处理在子孔径拼接检测处理中的有效性。     

Correction of wave-front errors caused by the slight tilt of a reference beam in phase-shifting interferometry

In standard phase-shifting interferometry the reference beam is supposed to be a plane wave exactly normal to the recording plane. A slight tilt of the reference beam, however, may occur in practice, and it will introduce phase distortion for the reconstructed object wave front. The effects of reference wave tilt on the wave reconstruction are analyzed, and a novel method is proposed to correct the errors caused by this tilt. This method is simple and convenient without the need of any additional optical devices and measurements, and it can be used for both the smooth and the diffuse object surfaces. The effectiveness of this method is verified by a series of computer simulations.     

猫眼光学误差的测量与修正

介绍了猫眼光学误差对激光跟踪三维坐标测量系统的影响及猫眼光学误差的主要来源,设计了一种猫眼光学误差的测量原理并构建了相应的测量装置,论述了测量数据处理方法以及在进行激光跟踪三维坐标测量时对猫眼光学误差进行修正的方法.在数据处理过程中,使用了非线性拟合算法来消除半球偏心和安装偏心对测量结果的影响,使用了二维插值算法来获取猫眼在任意入射方位角处的光学误差值.使用所构建的测量装置对Leica公司生产的CER75猫眼的光学误差进行了实际测量并对测量数据进行了处理.实验结果表明,被测猫眼在其接收角范围内的最大光学误差约为4μm.     

Optical design of a hollow cube-corner retroreflector for a geosynchronous satellite

The optical characteristics of a single-element hollow cube-corner retroreflector for a geosynchronous satellite were numerically evaluated for laser ranging and laser long-path absorption measurements of atmospheric species. An optical design with spherical surfaces and tuned dihedral angles was considered to compensate for velocity aberrations. The parameters for the retroreflector were optimized with genetic algorithms for different retroreflector sizes and wavelengths (500 nm and 1, 3, and 10 mum). We found that 20-cm retroreflectors are sufficient for realistic measurements when the laser wavelength is 500 nm or 1 mum. However, a larger retroreflector is necessary to overcome the detector noise level at 3 and 10 mum.     

Grating interferometry with a semiconductor light source

The properties of a fiber-optic-based grating interferometer with a laser diode as the light source are described. The influence of effects such as wavelength shift, line broadening, and mode hopping on the quality of an interference pattern is investigated both theoretically and experimentally. Introduction of carrier fringes in the interference pattern through the injection-current-induced modulation of a laser diode is shown. The requirements for temporal coherence properties of a light source in grating interferometry are given.     

Mirror hologram recording with a phase-change medium

We propose mirror hologram recording with a phase-change material, which has a large refractive-index difference between its amorphous and crystalline states. It offers excellent diffraction efficiency and is erasable and nonvolatile. We designed an optimum multilayer structure for high diffraction efficiency by simulating the effect of each film thickness on diffraction efficiency. Experiments with a germanium tellurium alloy as the phase-change material show a high diffraction efficiency close to the calculated value. This medium can also be used for directly drawing computer-generated holograms. Lee-type computer-generated holograms were drawn on this medium with optical-disk technology.     

The Laser Amplifier with a Stimulated Scattering Mirror

Abstract

A laser scheme with scattered volume employed as a cavity mirror is considered. The laser threshold and the output pulse characteristics are calculated.     

Dislocation interactions with tilt walls

The flow of plastic deformation in polycrystalline materials can be due to activation of sources in adjacent grains due to the effect of pile up dislocations against the grain boundary and also through the transmission of dislocations across the grain boundary. In this paper, we focus on these two issues by studying the evolution of resolved shear stress as a result of pile up dislocations against the boundary and understanding the basic phenomena of dislocation transmission through grain boundary. We also investigated the relaxed structures a grain boundary acquires after the process of dislocation transmission.     

Blurred image recovery by a phase-processing method with tilt correction

We present an improved method that incorporates tilt correction for blurred image recovery. A previously proposed method, which can compensate image blurring due to atmospheric turbulence, was improved to increase recovered image quality by correcting the tilt effect resulting from, e.g., a telescope's tracking jitter. Real-image analysis based on data from a 1.5 m diameter telescope with an infrared camera as well as from a computer simulation were performed. The results suggest that using the tilt-correction method yields an image quality that is much better than that obtained without the correction.     

Mirror recording system with a large field of view

A light-gathering system consisting of four mirrors with a large field of view has been developed. Two mirrors can be combined into one unit (double mirror). The design parameters of the system have been calculated and the problem on protection of the image plane from the foreign light has been considered. The objective proposed can be used in infrared imaging as well as in photometric and optical devices operating in the infrared region of the spectrum. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 6, pp. 178–183, November–December, 2005.     

Optical interferometry with pulsed fields

The problem of predicting and interpreting the results of interferometric optical experiments involving pulse trains is addressed. Specifically, a cyclostationary field arising from the modulation of a stationary, stochastic source is considered in the classical Young's experiment. It is shown that the effects of modulation may be identical to unrelated statistical interference effects.     

Holographic interferometry with multiple wavelengths

One of the unsolved problems in the well-established field of holographic interferometry is identification of zeroth-order fringes in cases in which the locations of zero displacement are unknown. We offer a simple solution: By making the double-exposure hologram of a white object in full color by using three or more wavelengths, the zeroth-order fringes will be indentified by their white color.     

Surface displacement imaging by interferometry with a light emitting diode

We present an imaging technique to measure static surface displacements of electronic components. A device is supplied by a transient current that creates a variation of temperature, thus a surface displacement. To measure the latter, a setup that is based on a Michelson interferometer is used. To avoid the phenomenon of speckle and the drawbacks inherent to it, we use a light emitting diode as the light source for the interferometer. The detector is a visible CCD camera that analyzes the optical signal containing the information of surface displacement of the device. Combining images, we extract the amplitude of the surface displacement. Out-of-plane surface-displacement images of a thermoelectric device are presented.     

Wavelength-scanning interferometry of a transparent parallel plate with refractive-index dispersion

Testing for flatness of an optical parallel plate in a Fizeau interferometer suffers from problems caused by multiple-beam interference noise. Each internal-reflection component can be separated from the signal by its modulation frequency in a wavelength-scanned interferometer; however, the frequency depends on the thickness and the refractive-index dispersion of the test plate and on the nonlinearity of the scanning source. With a new 19-sample wavelength-scanning algorithm we demonstrate the elimination of the reflection noise, the effect of the dispersion up to the second order of the reflectance of the test plate, and as the nonlinearity of the source. The algorithm permits large tolerance in the air-gap distance, thus making it somewhat independent of the thickness of the test plate. The minimum residual reflection noise with this algorithm for testing a glass plate is approximately lambda/600. Experimental results show that the front surface of the test plate was measured within 1 nm rms of its true shape over a 230-mm-diameter aperture.