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

    Authors

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

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    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

    Share

    COinS