Scattering of circularly polarized light in laser Doppler anemometry

Laser Doppler anemometry is based on light scattered from small particles in a fluid. When measurements are made near a surface the reflections from the surface may decrease the SNR of the Doppler bursts. This paper discusses a method to separate scattered light from reflected light by means of circularly polarized light. The relations describing the scattering of circularly polarized light are given and scattering diagrams are calculated for various Mie parameters and refractive indices. It is shown which collection angles, particle diameters and refraction indices should be used in LDA to efficiently quench the reflections from surfaces.