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

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.