Study of rough surfaces by light scattering.

The problem of the scattering of radiation from rough surfaces is formulated in the language of scalar coherence theory. An experiment is analyzed to show how the intrinsic properties of the scatterer can be studied quantitatively by making intensity measurements in the scattered field. This general formulation is applied to compare media that introduce random phase variation (e.g., a moving ground glass) with those that introduce random amplitude absorption. By introducing mathematical models that describe these two types of media we explicitly calculate the doppler broadening of the power spectrum and the condition of spatial incoherence. We show how it is possible to introduce a weaker condition to render the scattered field spatially incoherent for the purpose of optical imaging. We conclude that the statistical properties of the scattered field are affected much more by the media that introduce random phase than by those that introduce random amplitude absorption.