Cochran E R, Ai C
Appl Opt. 1992 Nov 1;31(31):6702-6. doi: 10.1364/AO.31.006702.
We describe a sensitive method for measuring the stress birefringence of an optical window that utilizes a phase-measuring Fizeau interferometer incorporating a variable retarder and a nonpolarizing beam splitter. When we test a material in an interferometer cavity, the wave front transmitted through the material is deviated by the surfaces, inhomogeneity, and birefringence of the material. Birefringence causes the transmitted wave front to have different optical path difference (OPD) profiles for the vertical and horizontal orientations of linear polarization. Subtracting these OPD profiles reveals the amount of phase difference between the fast and slow axes of the material. Hence, birefringence may be calculated. Phase-measurement techniques and a computer-controlled interferometer employing a variable liquid-crystal retarder provide a fully automated instrument for measuring stress birefringence. The theoretical derivation, discussion of the instrument, and experimental results are presented.
我们描述了一种用于测量光学窗口应力双折射的灵敏方法，该方法利用了一种结合了可变延迟器和非偏振分束器的相位测量菲佐干涉仪。当我们在干涉仪腔中测试一种材料时，透过该材料的波前会因材料的表面、不均匀性和双折射而发生偏移。双折射使得透过的波前对于线偏振的垂直和水平方向具有不同的光程差（OPD）分布。减去这些OPD分布就能揭示材料快慢轴之间的相差量。因此，可以计算出双折射。相位测量技术以及采用可变液晶延迟器的计算机控制干涉仪提供了一种用于测量应力双折射的全自动仪器。文中给出了理论推导、仪器讨论及实验结果。
