Strehl ratio probabilities for phase-only adaptive optic
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Authors
Ambrose, Charles R.
Subjects
Turbulence
Atmosphere
Adaptive
Optics
Laser
Propagation
Strehl
Computer
Probability
Atmosphere
Adaptive
Optics
Laser
Propagation
Strehl
Computer
Probability
Advisors
Walters, Donald L.
Fried, David L.
Date of Issue
1999-03-01
Date
March 1999
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Atmospheric turbulence will induce phase and amplitude fluctuations in propagating electromagnetic waves, such as a laser beam. Adaptive optical systems attempt to compensate for these distortions. The Strehl ratio is a measure of the peak, on-axis intensity after propagation through turbulence divided by the peak irradiance for vacuum propagation. This thesis investigated the probability distribution of the Strehl ratio of a perfect, phase-only, adaptive optical system as a function of the atmospheric coherence length Ro divided by the actuator spacing, d. Using an efficient Fourier algorithm and 28 workstations running in parallel, over 850 million computer simulations were performed for 25 different Ro/d ratios in order to produce a histogram of the irradiance probability distribution. The results show that the Strehl ratio follows a log-normal probability distribution even for very small probabilities. A second set of computer simulations introduced intensity scintillation by including the log-amplitude variance parameter, cu. sigma sub l. Much faster, state-of-the-art computer workstations enabled over two billion realizations on 18 machines running in parallel for comparable time periods. The trends of these results are more complex and will require further research and deeper investigation.
Type
Thesis
Description
Series/Report No
Department
Computer and Information Science
Operations Research (OR)
Identifiers
NPS Report Number
Sponsors
Funder
Format
viii, 71 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.