Berezhna S, Berezhnyy I, Takashi M
Appl Opt. 2001 Feb 10;40(5):644-51. doi: 10.1364/ao.40.000644.
It is shown that three optical parameters that are necessary for stress computation in integrated photoelasticity can be measured with high accuracy by use of a Fourier polarimetry method. Inasmuch as a photoelastic sample, which is an object of investigation in integrated photoelasticity, is a kind of an elliptic retarder, the technique presented here measures relative retardation delta, azimuth angle theta, and ellipticity angle epsilon instead of the characteristic parameters that traditionally have been used in integrated photoelasticity. The ability of the new technique to provide better accuracy with a simpler setup has been proved experimentally. Furthermore, the technique is self-contained as for phase measurement; i.e., it automatically performs phase unwrapping at the points where phase data exceed the value of pi. The full value of a phase at a certain point is retrieved by processing of pi-modulo phase data that have been precisely measured at several wavelengths. The usefulness of the new method for integrated photoelasticity has been demonstrated through measurement of a diametrically compressed disk viewed at oblique light incidence.
结果表明，利用傅里叶偏振测量法可以高精度地测量集成光弹性中应力计算所需的三个光学参数。由于集成光弹性研究对象的光弹性样品是一种椭圆延迟器，这里提出的技术测量的是相对延迟δ、方位角θ和椭圆率角ε，而不是传统上在集成光弹性中使用的特征参数。实验证明了该新技术在更简单的设置下能提供更高精度的能力。此外，该技术在相位测量方面是自包含的；即，它会在相位数据超过π值的点自动进行相位展开。通过处理在几个波长下精确测量的π模相位数据，可以获取某一点处相位的完整值。通过测量斜光入射下的直径压缩圆盘，证明了该新方法在集成光弹性中的实用性。
