Micro-polarizer array based instantaneous phase-stepping interferometry for observing dynamic phenomena

Abstract

We propose a method for determining phase distribution of interference fringes utilizing a CCD camera equipped with a micro-polarizer array. An optical setup of polarization interferometry using a Mach-Zehnder Interferometer with two polarizers is constructed to analyze the distribution of the thickness change of the transparent sample. Light emerging from the interferometer is recorded using a CCD camera that has a micro-polarizer array on a CCD plane. This micro-retarder array has four different principal directions. The four images separated from the image recorded by the CCD camera are reconstructed using gray level interpolation. Subsequently, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The phase distribution of the interference fringe pattern produced by the Mach-Zehnder interferometer is then obtained from these Stokes parameters. This method is applicable to dynamic phenomena because multiple exposures are unnecessary for sufficient data acquisition for phase analysis of fringes. © The Society for Experimental Mechanics, Inc. 2014.