Forward optical scattering from very rough surfaces near grazing incidence
Abstract
A series of metal and dielectric targets exhibiting fractal characteristics are produced having a range of surface roughness between about 1 and 16 microns. They are all sufficiently rough that only diffuse reflection was obtained from them when illuminated with an HE-Ne laser beam. The intensity scattered in the specular direction was measured as a function of the surface roughness for near normal (20 deg) and near grazing (85 deg) incidence. The specular direction intensity at first falls rapidly with increasing surface roughness, but then saturates at high values of the surface roughness. Good agreement is obtained between the experimentally observed variation with surface roughness and that predicted theoretically using a fractal surface scattering model and surface parameters measured using a profile instrument. A simple graphical model is used to demonstrate qualitatively the trends observed.
- Publication:
-
Unknown
- Pub Date:
- August 1990
- Bibcode:
- 1990fosv.rept.....J
- Keywords:
-
- Grazing Incidence;
- Light Scattering;
- Optical Measurement;
- Surface Roughness;
- Diffuse Radiation;
- Fractals;
- Helium-Neon Lasers;
- Mathematical Models;
- Specular Reflection;
- Optics