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We have observed the enhanced backscattering of light from a characterized dielectric film deposited upon a glass substrate when the light illuminates the rough surface from the vacuum. The vacuum-dielectric interface is one dimensional, randomly rough, while the dielectric-glass interface is approximately planar. Numerical and experimental studies reveal that the main mechanism responsible for the enhanced backscattering is the constructive interference between two waves that follow reciprocal scattering paths through the dielectric film, which is also strengthened by the multiple scattering from the rough vacuum-dielectric interface.

In this paper, we present the experimental resu'ts of the dynamic behavior of speckles from rough surface scattering to verify the validity of the theoretical analysis. Recently, McGurn and Maradudin have predicted an additional short-range correlation C(b0), which shows symmetry of speckles around the specular direction in the far-field scattering from a rough surface. We have measured this peak with a twodimensional rough dielectric film on a glass substrate. We have also measured the speckle trucking in the specular direction, the rotation invariance, and the time-reversed speckle memory effect with a onedimensional rough dielectric film on a glass substrate.

We present the experimental results of the angular correlation function of far-field speckle patterns scattered by a one-dimensionally random rough surface of a thin dielectric film on a glass substrate when a polarized beam of light is incident upon the rough surface from vacuum. This surface, which separates the vacuum and the dielectric, is rough enough that only diffused speckles are observed. The experiment for the correlation measurement was set up to make use of a CCD camera to obtain the image of the speckle pattern in the specular direction for each given angle of incidence; the cross-correlation function is then calculated from the digitized images. It is found that the intensity correlation functions exhibit two distinct maxima: one arises from the autocorrelation and the other from the reciprocity condition. It is also found that different scattering processes give rise to quite different correlation functions: multiple-scattering processes produce narrow peaks with secondary maxima and single-scattering processes produce relatively broad peaks.

An optical method of fabricating randomly rough one-dimensional surfaces is described. The variations in the surface profile are produced by exposing photoresist-coated plates to a narrow line of light and scanning them under computer control. A theoretical analysis of the basic statistical properties of the fabricated surfaces is presented. These surfaces are in general non-Gaussian, but their statistics can be easily calculated, making them attractive for experimental and theoretical work. Several such surfaces have been fabricated and characterized with a stylus profilometer. The estimated statistical properties are in agreement with the theoretical predictions.

We report the experimental study of the enhanced backscattering from a random rough surface through a laser dye-doped polymer. The sample is a slice of pyrromethene-doped polymer coupled with a two-dimensional rough gold layer with a large slope. When the sample is illuminated with an s-polarized He-Ne laser and pumped by a cw argon-ion laser, amplified backscattering is observed. The enhanced backscattering peak increases sharply and its width narrows for a sample with low dielectric constant |?(2)|.

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