CORRELATION PROPERTIES OF LIGHT SCATTERED FROM FLUIDS

The fluctuation and correlation properties of light scattered by a fluid are studied, without neglect of the spectral linewidth of the incident field. When the source is a single-mode laser, it is shown that, although the instantaneous amplitude of the scattered field obeys a Gaussian probability density, the scattered field is not a Gaussian field. The linewidth of the laser beam is reflected in the amplitude correlations of the scattered light, but not in the intensity correlations. On the other hand, when the laser is oscillating in more than one mode simultaneously, the spectral profile of the laser beam makes a contribution to the spectral density of the scattered intensity fluctuations, and cannot be neglected. © 1969 The American Physical Society.