Adaptive Control Over Extended Targets
Interim technical rept. 27 Sep 1975-27 Apr 1976
HUGHES RESEARCH LABS MALIBU CA
Pagination or Media Count:
Three types of adaptive optical systems are described that are being experimentally investigated. Each system is designed to be applied to high-power laser systems, to be insensitive to target effects, and to be effective in turbulence compensation. Two of the systems are multidither coherent optical adaptive techniques COAT and employ an imaging receiver. The imaging receivers employ image-plane aperture censoring techniques or IMPACT to enhance glint discrimination and, in some cases, to allow convergence on featureless target surfaces. The third system uses noncoherent light returned from the target to obtain phase corrections for a transmitted laser beam. Such systems, which may or may not use multidither techniques, are called TRIM-COAT because they combine transmitting and imaging COAT concepts. The one system studied to date uses an annular uncompensated receiver aperture and is known as Annular- Aperture IMPACT. This system operates like a conventional outgoing-wave multidither COAT system in strong turbulence, requiring a well-defined target highlight for good convergence. In low turbulence on the return path, however, the system has demonstrated its ability to converge a laser beam on a weak glint in the presence of a stronger one and to converge the beam on a featureless target.
- Lasers and Masers