Coherent backscattering of light

Abstract

Coherent backscattering of light (CBS) is a phenomenon in which partial waves traversing time-reversed (momentum-reversed) scattering paths interfere constructively in the backscattering direction leading to the appearance of an intensity cone. This increase in reflectivity reduces the amount of light transported through the colloidal media. As an advanced undergraduate laboratory CBS introduces the student to low-level light detection, precision angular resolved measurements, and sophisticated data analysis techniques. Additionally, the concept of photon self-interference, usually discussed in Modern Physics class in the context of Young’s double slit experiment, is beautifully illustrated by CBS.