Date of Award

12-1992

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Electrical and Computer Engineering

First Advisor

Byron M. Welsh, PhD

Abstract

Current adaptive optical telescope designs use a single deformable mirror (DM) to compensate for atmospheric distortion. The corrected field of view (FOV) of an adaptive optics system could be increased through the use of multiple DMs optically conjugated to corresponding planes which sample the turbulence region in altitude. Often, the atmospheric turbulence responsible for the degradation of telescope images is concentrated in several layers. Each DM would correct for the component of the total wavefront in the pupil contributed by one or more layers. If the atmosphere does not possess a layered structure, the best fit of the turbulence profile can be made to a layered model. This dissertation describes and analyzes two novel methods for estimating the proper DM surfaces which would result in wide-FOV compensation. Both methods use multiple wavefront sensor measurements to estimate the three-dimensional turbulence structure. The wavefront measurements are made using artificial guide stars created by scattered laser light. The analysis includes the effects of noise, realistic models of systems components, and the limitations of artificial guide stars. It is shown that multiple-DM, multiple-guide-star systems can significantly increase the compensated FOV relative to single-DM, single-guide star systems.

AFIT Designator

AFIT-DS-ENG-92-06

DTIC Accession Number

ADA258816

Download

Included in

Optics Commons

Share

COinS