Reciprocity relations of an electromagnetic light wave on scattering from a quasi-homogeneous anisotropic medium

The relationship between the properties of the far-zone field and the characteristics of the scattering medium for an electromagnetic light wave on scattering from a quasi-homogeneous anisotropic medium is investigated. It is shown that the spectral density and the spectral degree of coherence of the scattered field can be factorized as a product of two parts, the one is dependent on the polarization of the incident field, and the other is dependent on the characteristics of the medium. The medium-dependent part displays two reciprocity relations, i.e. the normalized spectral density of the scattered field is proportional to the Fourier transform of the normalized correlation coefficient of the scattering potential, and the spectral degree of coherence of the scattered field is proportional to the Fourier transform of the strength of scattering potential. An example of Gaussian-correlated, quasi-homogeneous, anisotropic medium is discussed to illustrate these reciprocity relations.