Title

Aperture averaging of optical scintillations: power fluctuations and the temporal spectrum

Authors

Authors

L. C. Andrews; R. L. Phillips;C. Y. Hopen

Comments

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Abbreviated Journal Title

Waves Random Media

Keywords

ATMOSPHERE; WAVES; MODEL; Physics, Multidisciplinary

Abstract

Using a recently developed theory of scintillation that is valid under all fluctuation conditions, including the focussing and saturation regimes, we develop general models for predicting power fluctuations (or aperture averaging) over finite-size collecting apertures. Inner-scale effects are introduced using a modified atmospheric spectrum for refractive-index fluctuations that includes a high-wavenumber bump. Where comparisons can be made, these models of aperture averaging are in good agreement with previous asymptotic models and experimental data. In addition to the aperture-averaging factor, we calculate the temporal spectrum associated with power fluctuations over various aperture sizes and conditions of turbulence. These later results clearly show the transfer of power distribution from high to low frequencies as the size of the collecting aperture is increased. The transfer of power is more pronounced in the saturation regime where high frequencies (fastest fluctuations) can be averaged out even for relatively small apertures.

Journal Title

Waves in Random Media

Volume

10

Issue/Number

1

Publication Date

1-1-2000

Document Type

Article

Language

English

First Page

53

Last Page

70

WOS Identifier

WOS:000085174800005

ISSN

0959-7174

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