Contribution of immersion technique to light scattering analysis of very rough surfaces

Abstract

Light intensity scattered from rough surfaces with heights exceeding the dimension of optical wavelengths is due to a large number of reflections from various oriented micro-areas. This phenomenon is theoretically interpreted by the vectorial method approximated to the first order, whether the rough surface is immersed or not. Experimental results concern two different scattering structures: a rough and a smooth ground glass. They verify that the angular distribution of the scattered flux is mainly related to the surface slope distribution. When immersion is used, this distribution is likely to involve the whole reflecting surface; otherwise a shadowing effect strongly reduces the contribution of higher slopes.