Polarization opposition effect and second-order ray tracing.
I develop a second-order ray-tracing model of the light scattered by a cloud of randomly oriented facets having sizes much larger than the incident wavelength. My results suggest that both symmetric and asymmetric branches of the polarization opposition effect can be produced by the same mechanism responsible for the photometric opposition effect, i.e., constructive interference of light rays traversing reciprocal paths that is associated with coherent backscattering enhancement. The model provides a greatly simplified representation of the physical phenomena to isolate the two mechanisms that may be responsible for the effect. The shapes and positions of the two branches of the polarization opposition effect calculated with the model are consistent with observation, so the model may provide a rapid technique to characterize the optical and physical properties of a scattering system. I note, however, that the model is a gross simplification containing only two physical mechanisms, Fresnel reflections and coherent interference, and it is possible that it represents a nonphysical description of particles smaller than the wavelength or that other mechanisms contributing to the polarization opposition effect are not included.
U.S. Army Research Laboratories, Adelphi, Maryland 20783-1197, USA. gvideen@arl.army.mil
Gorden
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Videen