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Proceedings Paper

Experiment to obtain optical turbulence information along a 2.33 km free-space laser propagation path from measurements of scintillation and focal spot displacement
Author(s): Arnold Tunick
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Paper Abstract

Optical turbulence research contributes to improved laser communications and adaptive optics systems. This paper presents experimental measurements of scintillation and focal spot displacement to obtain optical turbulence information along a near-horizontal 2.33 km free-space laser propagation path. Calculated values for optical turbulence intensity (C2n) and Fried parameter (r0) are compared to scintillometer-based measurements for several cases in winter and spring. Scintillation index estimates from recorded signal intensities were corrected to account for aperture averaging. Optical measurements provided better estimates for C2n and r0 when a more incoherent laser source was used during the second part of the experiment (λ= 808 nm) in comparison to a more coherent laser source (λ= 1064 nm) used for the first part. Apparently, an calculation criterion for this kind of laser signal analysis is that the propagating light beacon be partially incoherent and uniformly illuminated across the transmitting aperture. Similarly, estimates of C2n and r0 based on focal spot displacement analysis were improved using the more incoherent laser source, particularly in strong turbulence conditions.

Paper Details

Date Published: 20 August 2008
PDF: 9 pages
Proc. SPIE 7090, Atmospheric Optics: Models, Measurements, and Target-in-the-Loop Propagation II, 70900G (20 August 2008); doi: 10.1117/12.795519
Show Author Affiliations
Arnold Tunick, U.S. Army Research Lab. (United States)


Published in SPIE Proceedings Vol. 7090:
Atmospheric Optics: Models, Measurements, and Target-in-the-Loop Propagation II
Stephen M. Hammel; Alexander M. J. van Eijk; Mikhail A. Vorontsov, Editor(s)

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