Diffraction of Light Waves in an Inhomogeneous and Anisotropic Medium

Approximate solutions of Maxwell's equations in an anisotropic medium with the weak inhomogeneity are shown when monochromatic plane light waves are incident. One group of approximate solutions including the Raman-Nath diffraction in an anisotropic medium is derived by using the phase function method under the condition that the spatial variation of the medium is sufficiently small compared with that of the incident light waves. Another group of solutions derived by The use of the Born approximation includes both the normal Bragg diffraction and the abnormal one. The two solution types hold only in the neighbourhood of the boundary plane because of the conditions under which they are applicable.