Dynamic light scattering by using self-mixing interferometry with a laser diode

The power spectrum of the laser intensity is studied when optical feedback in a laser diode is used as a sensing configuration for dynamic light-scattering experiments. We present a theory that relates the power spectrum obtained from standard dynamic light-scattering theory to the intensity power spectrum of the laser. This theory provides a concise description of this sensing technique, also known as self-mixing interferometry, when it is applied to Doppler shift and line-broadening measurements of the backscattered field.