Near-Angle Scattering and Binary Optics
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The research objective was to measure near-angle scattering i.e., scattering less than one degree from the specular beam from a binary optic and determine if a scalar scattering theory could adequately predict scattering performance. Near-angle scattering was measured from a binary optic beam splitter. A scalar scattering theory was developed and modeled using fortran on a personal computer results from the computer simulation are compared to the actual measurements. The scalar scattering theory modifies Fraunhofer diffraction by including two types of surface topography which contribute to the scattering, specifically 1 surface roughness due to micro-irregularities which are considered to be randomly distributed and 2 large scale surface features i.e., the binary step pattern which are deterministic. The random surface roughness, the autocorrelation length of the roughness, and the height of the binary optics pattern were determined using a talystep surface profilometer. The scalar theory appears to give good results when compared to the measurements. However, higher values were required for the surface roughness and autocorrelation lengths than the talystep indicated, which may be due to the talysteps short scan length. Military and space applications for binary optics are also discussed. Theses.