Weak localization of photons: Termination of coherent random walks by absorption and confined geometry

Abstract

We compare the effects of finite thickness and absorption on the line shape of the coherent backscattering peak from a disordered medium. By termination of the coherent random walk of photons through confined goemetry and/or absorption, contributions of different time-reversed paths to the line shape of the backscattering peak have been determined. Using circularly polarized light, we find good agreement between the experimental and calculated line shape of the helicity-preserving channel whose coherent backscattering peak closely resembles that of a scalar field.