Theory of propagation of electromagnetic waves in transparent ferroelectric ceramics

Abstract

Propagation of electromagnetic waves in inhomogeneous dielectrics is considered within the framework of random field theory. We develop a method for solving problems associated with wave scattering by inhomogeneities of permittivity tensor ε(r). The method is applicable to the whole wave length range. Although we impose no restrictions on the nature of inhomogeneities, the only examples of inhomogeneous media considered in the paper are polarized segnetoelectrics, mono- and multiphase polycrystals. It is demonstrated that the effects due to coordinate dependence of ε can be revealed by analyzing the Fourier transform of effective permittivity tensor ε_*., Scattering index γ, phase ν_* and group 𝒸_* velocities are computed using the Bourret approximation with allowance for spatial dispersion. Asymptotic expressions for γ, ν_* and 𝒸_* are given for the long (compared to the effective dimensions of the scattering regions) wavelength range, short and ultrashort wavelength ranges.