One-shot measurement of birefringence by radial analysis

Abstract

Due to complexity and bulky configuration of conventionally mechanical rotation approaches, a more convenient approach is to measure the birefringence effect (phase retardation and fast axis) by nano-fabricated spatial devices. Previous literature introduced radially-polarized illumination and eliminated the need for rotation mechanics in the illumination optics but still required rotation devices in the analyzer part. This work aims to achieve a compact and one-shot birefringence measurement by introducing spatial concepts in both the modulator and analyzer. By proposing a novel birefringence measurement by the combination of radial illumination and radial analyzer, this work is the first time to integrate no-mechanical motion and one-shot birefringence measurement in a single light path. What’s more, we are the first to introduce Fourier analysis in birefringence measurement, replacing the previous average intensity calculation, which is easily influenced by light source fluctuations. Based on our one-shot & non-mechanical measurement design and Fourier analysis algorithm, our birefringence measurement achieved very stable phase retardation measurement (standard deviation < 0.3°) and high accuracy fast axis measurement (average absolute error < 0.04°).