Generalized algorithm for photoelastic measurements based on phase-stepping imaging polarimetry

A general method for measuring the birefringence of nondichroic, linear retarder media has been presented. The method is based on phase-stepping imaging polarimetry and permits the azimuth angle, phase retardation, and transmission coefficient of a sample to be calculated. The method uses a simple setup, a sample at rest, and permits fast acquisition of data. With the mathematical description applied, various algorithms for different optical configurations can be used and any number of intensity patterns can be generated. Experimental results for photoelastic samples and the results of measurements of the birefringence of optical components and biological samples are also presented.