POLARIZATION ASYMMETRY IN WAVES BACKSCATTERING FROM HIGHLY ABSORBANT RANDOM-MEDIA

Within the range in which light penetration depth is approximately the same as or less than the diameter of the particles in the medium, par ticulate media with considerable absorption behave as two-dimensional, rough-surface structures. As penetration depth increases, a complicat ed transition between volume and surface effects is seen. For these me dia, low-order scattering sequences have small spatial extent, making observation of polarization characteristics difficult. We present an e xperimental technique to access the low-order scattered photons by art ificially reinjecting them through total internal reflections. Using a dielectric layer in contact with the high-absorption medium, we are a ble to observe fourfold polarization asymmetry in backscattering from highly absorbant media. We discuss the origin of the polarization patt erns in a ray-optics approximation and suggest possibilities for solvi ng practical problems encountered in characterizing composites with ap preciable absorption. (C) 1997 Optical Society of America.