Abstract

A new method is described for the explicit determination of the refractive index amd extinction coefficient of an opaque film deposited on a transparent substrate from purely angular, nonpolarimetric, measurements. In particular it is shown that the real and imaginary parts of the complex dielectric constant ε = ε_{r –j} ε_i of the film are obtained analytically, directly and noniteratively, from the pseudo-Brewster angles (PBAs) of internal and external reflection. This follows from a study of the properties of the contours of constant PBA in the complex ε plane. For this method to be accurate, one of the two PBAs should be <45°, i.e. the substrate should be sufficiently optically dense or the UV and VUV spectral range is of interest. Experimental errors of the PBAs may also render impossible the determination of ε_i when |ε_i/ε_r|≪1. Simulated measurements on Ag and TiN films will be presented to demonstrate the method.

© 1988 Optical Society of America