Reducing the berreman 4x4 propagation matrix method for layered inhomogeneous anisotropic media to the ahel^s 2x2 matrix method for isotropic media

With the use of the exact expression for the local propagation matrix that was obtained by Wohler et al. [J. Opt. Soc. Am. A 5, 1554 (1988)], we show explicitly that the Berreman 4X4 propagation matrix method for layered inhomogeneous anisotropic media reduces to the Abeles 2X2 propagation matrix method for layered inhomogeneous isotropic media when the anisotropic medium becomes isotropic. © 1991 Optical Society of America.