Simultaneous measurement of refractive index and thickness of transparent films by white-light interferometry

Abstract

We propose a new method for simultaneous measurement of refractive index and physical thickness of transparent films by use of an interferometric surface profiler. It is based on a combination of two techniques which we have proposed recently. Firstly the target film is inserted into the measuring optical path, and the surface height change of a back-mirror surface is measured. Then the optical thickness is measured from the two peak positions in the interferogram. From these two measurements, we can obtain the refractive index and thickness of the film separately. The experimental results verify the feasibility of this method.