We study Wigner phase-space distributions W(x, p) in position (x) and momentum (p) for light undergoing multiple small-angle scattering in a turbid medium. Smoothed Wigner phase-space distributions are measured by using a heterodyne technique that achieves position and momentum resolution determined by the width and the diffraction angle of the local oscillator beam. The sample consists of 5.7-μm-radius polystyrene spheres suspended in a water–glycerol mixture. The momentum distribution of the transmitted light is found to contain a ballistic peak, a narrow diffractive pedestal, and a broad background. The narrow diffractive pedestal is found to decay more slowly than the ballistic peak as the concentration of scatterers is increased. The data are in excellent agreement with a simple theoretical model that explains the behavior of the narrow pedestal by including multiple diffractive scattering and treating large-angle scattering as a loss.
© 1998 Optical Society of America
(040.2840) Detectors : Heterodyne
(110.7050) Imaging systems : Turbid media
(170.1650) Medical optics and biotechnology : Coherence imaging
(290.4210) Scattering : Multiple scattering
(290.5820) Scattering : Scattering measurements
A. Wax and J. E. Thomas, "Measurement of smoothed Wigner phase-space distributions for small-angle scattering in a turbid medium," J. Opt. Soc. Am. A 15, 1896-1908 (1998)