A method for measuring two-dimensional refractive index distribution by using Fresnel equations and phase-shifting interferometry

摘要

Based on Fresnel equations and the phase-shifting interferometry, an alternative method for measuring the two-dimensional refractive index distribution of a material is presented. A linearly polarized light passes through a quarter wave-plate and is incident on the tested material. The reflected light propagates through an analyzer, and then the interference signal can be obtained. The special equations to es-rntimate the phase of the interferometric signal can be derived by using Fresnel equations. Next, the associated two-dimensional phase distribution is measured by the four-step phase-shifting interferometry. Then, the measured data are substituted into the special equations derived previously, and the two-dimensional refractive index distribution of the tested material can be obtained.