Compact and Robust Beam Steering for IRCM Applications

A technique based on a pair of in-line cesium bromide prisms is proposed for the rapid and reliable steering of a 5-watt laser beam as part of an Infra-Red Counter-Measure system for use in naval aircraft. To steer the beam, both prisms are rotated aboutan axis coincident with the incoming laser beam axis. By using prisms with a 24¿ angle, laser beams with a wavelength between 0.5 micron and 5.0 microns can be steered in any direction up to 45¿ from the incoming beam axis. This range can easily beincreased by adding a reverse telescope immediately following the prism pair. The beam steering angle is to first order insensitive to tilts and displacements of the prism pair, and the prism/motor structure is compact and has a high mechanical resonantfrequency. These factors work to minimize the systems sensitivity to vibrations. The approach is based on mature technologies and should lead to a robust, reliable, accurate, and economical solution to the Navy's beam-steering problem. Static in-linebeam-steering, continuous spiral laser beam scans, high-speed and high-resolution random access beam-steering with very high optical efficiency.