Birefringence by a smoothly inhomogeneous locally isotropic medium

Abstract

Propagation of an electromagnetic wave in a layered locally isotropic medium is considered. An effective birefringence ${\mathit{n}}_{\mathrm{\ensuremath{\parallel}}}$-${\mathit{n}}_{\mathrm{\ensuremath{\perp}}}$\ensuremath{\sim}(\ensuremath{\lambda}/a${)}^{2}$ for the \ensuremath{\parallel} and \ensuremath{\perp} eigenpolarizations appears, and the corresponding phase difference ${\mathit{cphi}}_{\mathrm{\ensuremath{\parallel}}}$-${\mathit{cphi}}_{\mathrm{\ensuremath{\perp}}}$\ensuremath{\sim}(\ensuremath{\lambda}/a) is calculated in this paper. An alternative method of calculation of the higher (\ensuremath{\sim}\ensuremath{\lambda}/a) WKB corrections for the one-dimensional Schr\"odinger problem is developed as a by-product of the work.