The problem of light scatter from optical surfaces is amplified to a critical level for the optics used in the Ring Laser Gyro (RLG). This has led to the development of a scatterometer at the RLG Lab, Wright-Patterson AFB, which can detect low level light scatter from the high quality optics used in RLG's, without first overcoating with metals. A helium-neon laser is used to illuminate a 0.5 mm diameter spot on the surface of the test part. The incident angle can be varied from 0 to 90 degrees, and the test piece can be maneuvered with five degrees of freedom, four of which are computer controlled. Scatter measurements are made with a photomultiplier detection system which can easily measure down to 10 parts per billion per steradian. The computer can analyze and plot the results very quickly and accurately for further interpretation.

Date Published: 5 April 1983
PDF: 7 pages
Proc. SPIE 0362, Scattering in Optical Materials II, (5 April 1983); doi: 10.1117/12.934147

Published in SPIE Proceedings Vol. 0362:
Scattering in Optical Materials II
Solomon Musikant, Editor(s)