A Prism Line-scanner for High-speed Thermography

Thermographic instruments using single-element line scanning usually have very low line frequencies in comparison with television. To meet the requirements for higher frame rates in thermography and infra-red viewing a line scanner with an indium antimonide detector and a rotating germanium prism has been designed. It produces heat images with 100 lines per frame on a television-type display tube at a flicker-free frame rate. The sweep efficiency of the scanning system is almost 100 per cent. The optical aberrations introduced by the scanning prism are analysed and found to be at a minimum when the refractive index lies between 3 and 4. Examples of heat pictures taken with different modes of operation are given.     

Fourier transform near-infrared spectrometer using a corner-cube integrated prism scanning interferometer

This paper describes a Fourier transform (FT) near-infrared spectrometer that uses an integrated prism scanning interferometer whose optical paths are stabilized by corner cubes. A combination of corner cubes and a retroreflection mirror, which is sometimes used in the conventional interferometer for FT spectrometers, is adopted and adapted to the integrated prism scanning interferometer through a special design. Without any degradation of spectroscopic properties, the optical path in the interferometer is highly stabilized and the moving distance of the stage is halved. These advantages provide a robust and portable FT spectrometer for field use.     

Two-dimensional thickness measurements based on internal reflection ellipsometry

An imaging ellipsometer technique on internal reflection geometry that can measure the thickness distribution of a thin film possessing an assumed refractive index is described. Because a prism is used for the internal reflection geometry, it was theoretically predicted that angular derivation from the normal incidence on the prism surface affects only the psi value by a factor of 0.97 at maximum. Measurements were carried out for an optical system of silica substrate-TiO2 layer-silica layer-protein film-air, with a thin-film array of dried protein as the sample film. Thickness of the protein films was two-dimensionally estimated only from the measured map of the delta value by use of the simulated relationship between the thickness and the delta value. The thickness map obtained was coincident on the whole with the results according to a mechanical scanning. The detection limit was approximately +/- 0.2 nm. These findings validate the optical effect of a high-index additional layer to improve the sensitivity and precision of thickness measurements of the sample film on transparent substrates.     

Kilohertz scanning optical delay line employing a prism array

A kilohertz scanning optical delay line is demonstrated by means of employing a prism array formed by identical wedge prisms. The wedge prisms are lined up with one another and uniformly disposed on a rotational wheel. The optical path length of a light beam can thus be scanned as the prisms pass through the beam periodically. Scanning rate of 2 kHz, scanning amplitude of 3.5 mm, linearity of 99%, and duty cycle of 95% can be achieved simultaneously. Simplicity and rigidity are embedded in the design. Preliminary test results are presented.     

Hybrid normal-reverse prism coupler for light-emitting diode backlight systems

For the first time to our knowledge, a hybrid normal-reverse prism coupler was formed on the bottom surface of a light guide in a LED backlight system to achieve a thin, lightweight, LED backlight system. The hybrid prism coupler (HPC) simultaneously exhibits two functions: extraction of guided light from the light guide and focusing the radiated light from the light guide, corresponding to the optical functions of the prism and diffusive sheets used in conventional LED backlight systems. Therefore, using a HPC eliminates the prism and diffusive sheets that have been indispensable optical elements in conventional LED backlight systems, which consequently reduces the thickness of the LED backlight system by 40% compared with conventional systems.     

基于光学定心加工的道威棱镜装配方法

本论文针对如何实现道威棱镜光轴与旋转轴平行,将道威棱镜转像理论与光学定心加工结合,提出了基于光学定心加工的道威棱镜组件装配方法.该方法根据道威棱镜旋转轴偏转时其出射光束发生变化的特性确定道威棱镜光轴,并通过车削的方式保证其镜筒外圆旋转轴与其光轴平行.本文具体提出两种道威棱镜组件定轴方案,分别为平行光管定轴方案以及激光定...     

Method for producing correct fingerprints

The conventional method of producing fingerprints by total internal reflection using a right-angle prism does not give true size images. In this case an anamorphic real image is formed by the Scheimpflug condition with keystone distortion. A method of combining a single prism with the right-angle prism for anamorphic stretching to get the correct fingerprint image is described. The method of constructing such a type of an optical system is discussed in detail. The method is useful to directly obtain the correct fingerprints using a CCD camera.     

Scanning delay line with a rotating-parallelogram prism for low-coherence interferometry

We describe a fast scanning optical delay line for low-coherence interferometry that has good linearity, a high duty cycle, and a continuously adjustable scan range. The delay line consists of a rotating-parallelogram prism with the rotation axis tilted with respect to the incident beam and two motionless mirrors. The delay line is well suited for nearly simultaneous distance measurements at two different depths, which is useful for making absolute and differential distance measurements.     

Nonmechanical transverse scanning laser Doppler velocimeter using wavelength change

A transverse scanning laser Doppler velocimeter (LDV) that does not require any moving mechanism in its sensor probe is proposed, and the scanning function is demonstrated theoretically and experimentally. In the proposed scanning LDV, the measurement position is transversely scanned on the basis of a wavelength change induced by a tunable laser and a combination of a grating and a Dove prism. To demonstrate the scanning function in the transverse direction, an experiment was carried out using a setup of the sensor probe consisting of bulk optical components. The experimental results indicate that a transverse scanning function was successfully obtained. The scanning range in the vertical direction is estimated to be 11.3 mm over wavelengths of 1520 to 1570 nm.     

光学相关器系统的固化设计与性能分析

小型固化光学相关器,以偏振分光棱镜和反射型傅里叶透镜作为基本部件,并采用透明固体介质填充光学系统的空隙。该系统通过各元件端面相连,简化了校准难度;使用反射型透镜,具有色像差和轴外像差小的优势。模拟分析表明,这种固化结构具有良好的系统性能,并满足识别的需要。     

Dove棱镜的加工误差对耦合损耗的影响

平行光束经过有加工误差的Dove棱镜后,在出射面往往会发生角度倾斜和离轴偏差,从而导致利用Dove棱镜制成的光纤旋转连接器的传输耦合损耗增大。对于Dove棱镜的加工误差在耦合损耗方面的影响,本文利用光线追迹的方法对其进行了理论及模拟分析。分析结果显示,由于加工误差带来的耦合损耗随着Dove棱镜的底角误差及其锥体角误差的增加而增大。而后依据理论结果及光纤旋转连接器的需求,设计加工了5块Dove棱镜,测量了其耦合损耗,并对实验测量值进行了修正,进一步验证了理论的正确性。     

Visible-regime polarimetric imager: a fully polarimetric,real-time imaging system

A fully polarimetric optical camera system has been constructed to obtain polarimetric information simultaneously from four synchronized charge-coupled device imagers at video frame rates of 60 Hz and a resolution of 640 x 480 pixels. The imagers view the same scene along the same optical axis by means of a four-way beam-splitting prism similar to ones used for multiple-imager, common-aperture color TV cameras. Appropriate polarizing filters in front of each imager provide the polarimetric information. Mueller matrix analysis of the polarimetric response of the prism, analyzing filters, and imagers is applied to the detected intensities in each imager as a function of the applied state of polarization over a wide range of linear and circular polarization combinations to obtain an average polarimetric calibration consistent to approximately 2%. Higher accuracies can be obtained by improvement of the polarimetric modeling of the splitting prism and by implementation of a pixel-by-pixel calibration.     

Cone prism: principles of optical design and linear measurement of the applanation diameter or area of the cornea

The cone prism introduced is mainly used in applanation tonometers to act as an applanation prism for linear measurement of the applanation diameter or the applanation area of the cornea. Its principles of optical design and linear measurement are expounded in detail. The measuring body, which comprises the cone prism and other optical and electronic parts, is also briefly introduced.     

四通道单模光纤旋转连接器的研制

设计了一种基于道威棱镜的光传输特性的四通道单模光纤旋转连接器,采用锥齿轮行星轮结构实现光信号的旋转耦合,并设计了耦合调整方案;分析道威棱镜光轴与旋转轴不重合带来的耦合损耗,确定道威棱镜的装调精度。最终使四通道单模光纤旋转连接器的技术指标达到了国外同类产品水平,且道威棱镜的通光孔径大,可在结构尺寸不变的情况下直接扩展为八通道单模光纤旋转连接器。     

Accurate measurement of interferometer group delay using field-compensated scanning white light interferometer

Interferometers are key elements in radial velocity (RV) experiments in astronomy observations, and accurate calibration of the group delay of an interferometer is required for high precision measurements. A novel field-compensated white light scanning Michelson interferometer is introduced as an interferometer calibration tool. The optical path difference (OPD) scanning was achieved by translating a compensation prism, such that even if the light source were in low spatial coherence, the interference stays spatially phase coherent over a large interferometer scanning range. In the wavelength region of 500-560 nm, a multimode fiber-coupled LED was used as the light source, and high optical efficiency was essential in elevating the signal-to-noise ratio of the interferogram signal. The achromatic OPD scanning required a one-time calibration, and two methods using dual-laser wavelength references and an iodine absorption spectrum reference were employed and cross-verified. In an experiment measuring the group delay of a fixed Michelson interferometer, Fourier analysis was employed to process the interferogram data. The group delay was determined at an accuracy of 1×10(-5), and the phase angle precision was typically 2.5×10(-6) over the wide wavelength region.     

别汉棱镜的旋像精度分析和装校方法

本文详细讨论了别汉棱镜组的装校误差对光轴偏折的作用,分析了三轴装配误差对像点运动精度的影响,并给出了装配及检测别汉棱镜系统的一种有效方法。     

激光扫描法外径测量的实验研究

本文讨论了转镜扫描激光非接触外径测量系统中主要部件(扫描用多面棱镜、准直和成像透镜)的设计,并给出参数计算公式和典型的数值计算。用现有的实验装置进行验证,其实验结果与理论分析结论符合较好,从而证实了本文提出的该测量方法的主要误差源为脉冲时间间隔测量误差、准直透镜焦距误差和脉冲重复频率误差,为进一步改进这种转镜扫描法的测试仪器提供了参考依据。     

单频激光干涉仪四通道信号接收系统

在单频激光干涉仪四通道信号接收系统原理基础上,提出一种采用Wollaston棱镜的四通道信号接收系统。当使用偏振分光镜的四通道信号接收系统时,由于偏振混合现象,在信号接收的过程中会增加额外的误差。而Wollaston棱镜的自然物理特性提供了更好的分光性能,从而能降低偏振混合所带来的影响,提高了信号输出质量,并能简化接收系统中的光学元件。     

波前分割无掩模激光干涉光刻的实现方法

激光干涉光刻不受传统光学光刻系统光源和数值孔径的限制,其极限尺寸CD达到曝光波长 的1/4,研究了波前分割双光束、三光束方法及四光束无掩模激光干涉光刻方法,提出了可用于五光束和多种多光束和多次曝光的梯形棱镜波前分割干涉光刻方法。用自行建立的梯形棱镜波前分割系统进行了多光束干涉曝光实验,得到孔尺寸约220nm的阵列图形。     

光盘光学头整形棱镜光学系统的设计

针对激光光盘系统的特点，重点讨论在单块整形棱镜优化设计中的光学问题。