The range of incidence angle, 0 < φ < φe, over which p-polarized light is reflected at interfaces between transparent and absorbing media with reflectance below that at normal incidence is determined. Contours of constant φe in the complex plane of the relative dielectric constant ε are presented. A method for determining the real and imaginary parts of the complex refractive index, ε1/2 = n + jk, which is based on measuring φe and the pseudo-Brewster angle φpB, is viable in the domain of fractional optical constants, n, k < 1.
Journal of the Optical Society of America A
R. M. A. Azzam and Ericson E. Ugbo, "Angular range for reflection of p-polarized light at the surface of an absorbing medium with reflectance below that at normal incidence," J. Opt. Soc. Am. A 19, 112-115 (2002)