Determination of refractive index, extinction coefficient and thickness of thin films by the method of waveguide mode excitation

Abstract

We propose a method for measuring simultaneously the refractive index , extinction coefficient and thickness of thin films. The method is based on the resonant excitation of waveguide modes in the film by a TE- or a TM-polarised laser beam in the geometry of frustrated total internal reflection. The values of , and are found by minimising the functional , where and are the experimental and theoretical coefficients of reflection of the light beam from the interface between the measuring prism and the film at an angle of incidence . The errors in determining and by this method are and , respectively.