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On the use of Gaussian filter functions for adaptive optics
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Paper Abstract

For adaptive optic systems, the use of aperture filter functions calculated using various Zernike modes can be useful in describing lower-order aberrations caused by atmospheric turbulence. Traditionally, these filter functions are calculated using the step function depicting a hard aperture that introduces integrals that are sometimes difficult to integrate and must be done numerically. The Gaussian method, equivalent to the ABCD matrix method, can be used in place of the conventional method for calculating the aperture filter functions. Evaluation of the Gaussian approximation for modeling a finite receiver aperture can be made by comparison of reduction in phase variance with results achieved using the conventional method. The validity of Gaussian approximation in this application is demonstrated by the consistency of results between the two methodologies. Comparison of reduction in scintillation by the two methodologies reveals several benefits derived from utilization of Gaussian approximation. The Gaussian approximation produces data that can be interpreted analytically. This paper will first examine the use of statistical models for predicting atmospheric turbulence and then the use of Zernike polynomials in adaptive optics. Next, this paper compares the reduction of phase variance and scintillation using the conventional method with the Gaussian approximation to evaluate the effectiveness of the new filter functions. The results of these comparisons are presented both as mathematical expressions and graphically.

Paper Details

Date Published: 12 February 2007
PDF: 12 pages
Proc. SPIE 6457, Free-Space Laser Communication Technologies XIX and Atmospheric Propagation of Electromagnetic Waves, 64570Q (12 February 2007);
Show Author Affiliations
Merfit Assad, Lockheed Martin Co. (United States)
Larry C. Andrews, Univ. of Central Florida (United States)

Published in SPIE Proceedings Vol. 6457:
Free-Space Laser Communication Technologies XIX and Atmospheric Propagation of Electromagnetic Waves
Steve Mecherle; Olga Korotkova, Editor(s)

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