Abstract

In general, the optical field scattering from a randomly rough surface can be divided into a specular or coherent component, and a diffuse or incoherent one. It is also well known that optically rough surfaces extinguish the specular component and thus produce only diffuse light. In normal circumstances, the diffuse component is a smoothly varying envelope that modulates the speckle field. However, recently it has been reported that light scattered from randomly rough surfaces with even symmetry displays a very sharp peak in the specular direction.^(1-2) The width of this peak is of order 2λ/L, where L represents the length of the illuminated portion of the surface, and λ represents the wavelength of the light. It must be stressed that this peak is not due to the presence of an unscattered component, as would be the case for a weakly scattering surface; the peak is part of the diffuse component. In previous work, this effect has been termed, in reflection, specular enhancement, and in transmission, enhanced refraction. In this paper, we shall refer to this effect as the specular enhancement.

© 1992 Optical Society of America