P-polarized reflectance method and its applications to film parameter measurement and optical sensing

Abstract

It is well known that the reflection characteristic data of a polarized laser beam from a coated flat plate provide enough information, with which one can understand the properties about the coating. For this purpose several techniques have been developed, among them so called ellipsometry is a typical one. However, to search novel approaches of p-polarization method, by which sensitive and compact device can be designed, is still of importance not only for determining film's optical parameter but also for optical sensing. Because the measured change of some film's parameter shows the quality of the environment, where the film locates. In this paper we present a new approach, of which the basic idea is to measure reflectance ratio angular spectrum /spl gamma/(/spl theta//sub i/) of a sample with a p-polarized laser beam at wavelength of /spl lambda/, where /spl gamma/(/spl theta//sub i/)=I/sub a/(/spl theta//sub i/)/I/sub b/(/spl theta//sub i/), I/sub a/ and I/sub b/ are the intensities of the beams from front and rear surface, /spl theta//sub i/ is the incident angle.