【作者】 林远芳； 郑赪； 郑晓东； 王晓萍； 刘旭； 刘向东；

【Author】 LIN Yuan-fang,ZHENG Cheng,ZHENG Xiao-dong,WANG Xiao-ping,LIU Xu,LIU Xiang-dong(State Key Laboratory of Modern Optical Instrumentation,Department of Optical Engineering,Zhejiang University,Hangzhou 310027,China)

【机构】 浙江大学光电信息工程学系 现代光学仪器国家重点实验室；

【摘要】 提出了通过编写和运行ASAP光学软件的命令脚本来模拟单轴晶体锥光干涉的方法。脚本中的命令主要有:设定光源波长、晶体寻常光和非常光折射率、光轴方向;定义起偏器、晶体、检偏器和观察屏的几何形状和光学特性;产生一组光线并设置其相干性、波动性和角度特性;将近基光线数设为4以完成对以基线为中心的高斯光束的定义;在光线追迹中利用菲涅尔公式为每条光线重新计算分界面上两偏振分量的反射和透射系数;精确计算复杂干涉场的能量分布并加以显示。模拟结果表明:该方法能仿真任意光轴取向的单轴晶体锥光干涉图。光轴垂直于折射表面时,干涉图为以光轴为圆心且被十字分割的内密外疏的同心圆环,并且:当起、检偏方向由互为垂直逐渐转为平行时,干涉图随之转动直至图样互补;增加晶体厚度、减小光源波长或增大其发散角时,圆环向内收缩且环数增加,反之亦然。光轴平行于折射表面时,干涉图为两组对称轴分别平行和垂直于光轴方向的同轴双曲线,当光轴绕着折射表面法线转动时,干涉图随之转动且视场亮度发生变化,当两倍光轴方位角的正弦值为0时,视场最暗;为1时,视场最亮,干涉条纹对比度最好。更多还原

【Abstract】 A method of simulating conoscopic interference in uniaxial crystal through writing and running an ASAP command script was presented.Main commands were as follows: Define the wavelength,refractive indices of ordinary and extraordinary ray,optical axis direction.Define geometries and optical properties of a polarizer,a crystal,an analyzer and an observing plane.Create a set of rays and specify their coherence,propagation and angular properties.Sets the number of parabasal rays be equal to four so as to define general Gaussian beams centered on each base ray.Recalculate separately the reflection/transmission coefficients of both polarizations specified on an interface for each ray using Fresnel’s formulae during a ray trace.Calculate and display the exact complex field energy distribution characteristic.Simulation results show that,the method can simulate conoscopic interferograms for any orientation of optical axis in a uniaxial crystal.When the optical axis is perpendicular to the refractive surface,the interferogram consists of concentric rings centered on the optical axis and is separated by a cross.The ring density is decreasing from inside to outside.While directions of the polarizer and the analyzer changing from perpendicular to parallel to each other,the interferogram rotates until complementary pattern appears.Once increase the c rystal thickness,reduce the wavelength or increase the divergence angle,rings will shrink inside and their numbers increase,and vice versa.When the optical axis is parallel to the refractive surface,the interferogram consists of two sets of coaxial hyperbola with their axis of symmetry separately perpendicular and parallel to the optical axis.While the optical axis rotates aro und the refraction surface normal,the interferogram also rotates and the brightness of the field changes.When sine of double azimuth of the optical axis is equal to zero,the field is darkest.Equal to 1,the field is brightest and interference fringes contrast is the best.更多还原