Recent Developments In The Analysis Of Surface Scatter Phenomena

Scattering effects from rough surfaces are non-paraxial diffraction phenomena resulting from random phase variations in the reflected wavefront. Rayleigh-Rice (1951) or Beckmann-Kirchhoff (1963) theories are commonly used to predict surface scatter effects. Also, Harvey and Shack (1976) developed a linear systems formulation of surface scatter phenomena in which the scattering behavior is characterized by a surface transfer function. This treatment provided insight and understanding not readily gleaned from the two previous theories. However, smooth surface and/or paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. A new linear systems formulation of non-paraxial scalar diffraction theory applied to surface scatter phenomena resulted first in a modified Beckmann-Kirchhoff surface scattering model, then a generalized Harvey-Shack theory that produces accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident angles than the classical Beckmann-Kirchhoff theory. These new developments simplify the analysis and understanding of stray light resulting from non-intuitive scattering behavior from rough surfaces illuminated with large incident angles