An unperturbing theory of a fixed scatterer embedded in a random medium based on the Bethe–Salpeter (BS) equation formalism is developed. The BS equation is subject to a coordinate-interchange invariance, and from that we can, to a considerable extent, find a basic structure of the BS equation without knowing details of the specific random medium involved, which leads to enhanced backscattering. A fixed scatterer embedded in the medium changes the basic equations, according to a simple principle, in such a way that the BS equation formally remains unchanged. Effective scattering matrices of the fixed scatterer are investigated in detail, including both a shadowing effect and enhanced backscattering.
© 1993 Optical Society of America
Original Manuscript: June 1, 1992
Published: May 20, 1993
Koichi Furutsu, "Fixed scatterer in a random medium: shadowing, enhanced backscattering, and the inner structure of the Bethe–Salpeter equation," Appl. Opt. 32, 2706-2721 (1993)