Precision analysis of polarization interference method for measuring stress birefringence of crystal

A method based on polarization interference method was proposed to precisely measure the stress birefringence of optical crystal. A sphenoid specimen was adopted to avoid measurement error caused by the thickness of specimen. Using the theory of elliptical polarized light and Jones matrix, the analytic expressions for measurement error of optical path difference caused by the rotating positional accuracy of the analyzer, the phase deviation of the quarter wave plate and the azimuth error of specimens under test were derived respectively. The results of error analysis indicate that the measurement error of optical path difference caused by the rotating positional accuracy of the analyzer is the largest, which reaches 3.1 nm when the rotating positional accuracy of the analyzer is 10'. Besides, the measurement error of optical path difference caused by the azimuth error of the specimens under test is intermediate, which reaches 0.7 nm when the azimuth error of the specimens under test is 1° and finally the measurement error of optical path difference caused by the phase deviation of the quarter wave plate is the smallest, which reaches 0.1 nm when the phase deviation of the quarter wave plate is 1.5°.