Measurement of phase retardation and fast axis of a quarter-wave plate using vector beams and Fourier analysis

Abstract

This work presents a novel method to simultaneously measure a quarter-wave plate's phase retardation and fast axis using radially polarized vector beams and spatial Fourier analysis. The light beam is converted into a radially polarized beam after passing through a polarizer and a vortex retarder. The tested quarter-wave plate and a polarizer are placed after the vortex retarder in sequence, and an hourglass intensity distribution image is recorded by a camera. Then the phase retardation and fast axis of a quarter-wave plate can be calculated by using Fourier analysis of the recorded intensity image with a snapshot. The theoretical model of the proposed method is built based on the Stokes-Mueller formalism. And both simulation calculation and experiments are carried out with different fast axis angles of a quarter-wave plate. The measurement errors of the phase retardation and fast axis are also analyzed to validate the proposed method. Both simulation calculation and experimental results show good agreement with the theoretical values. It is demonstrated that the proposed method is convenient, simple, and accurate to measure the phase retardation and fast axis of a quarter-wave plate.