Accession Number : ADA339170
Title : Active Optics: A New Technology for the Control of Light
Corporate Author : LITTON INDUSTRIES INC LEXINGTON MA ITEK OPTICAL SYSTEMS
Personal Author(s) : Hardy, John W.
Report Date : JUN 1977
Pagination or Media Count : 118
Abstract : Active optical systems are those in which real-time control over optical wavefronts is employed to optimize system performance in the presence of random disturbances. Applications include (1) outgoing-wave systems for maximizing the power density of a laser beam on a target and (2) received-wave systems for maximizing the angular resolving power of a telescope viewing a distant object through a turbulent atmosphere. In this tutorial/review paper, the basic concepts of active optics systems and their historical evolution are discussed, from early figure-control systems with a servo bandwidth of less than 1 Hz to the recently developed high-bandwidth systems for atmospheric compensation with bandwidths of several hundred hertz. A critical comparison of the various approaches to wavefront sensing is then made covering both coherent (laser) and incoherent (white-light) systems. Current techniques for wavefront correction, including Bragg cells, segmented mirrors, thin-plate deformable mirrors, monolithic mirrors, and membrane mirrors are described. The performance analysis and optimization of closed-loop systems is covered using two basic models. The paper concludes with a review of the design and performance of five current experimental active optical systems, with some comments on future applications.
Descriptors : *ADAPTIVE OPTICS , MIRRORS , REAL TIME , ACTUATORS , BANDWIDTH , WAVEFRONTS , CLOSED LOOP SYSTEMS , TELESCOPES , BRAGG ANGLE , PHASE CONJUGATION.
Subject Categories : OPTICS
Distribution Statement : APPROVED FOR PUBLIC RELEASE