Measurements of 0.63mm Laser-beam Scintillation in Strong Atmospheric Turbulence
Measurements of 0.63mm Laser-beam Scintillation in Strong Atmospheric Turbulence

Author: G. R. Ochs

Publisher:

Published: 1969

Total Pages: 28

ISBN-13:

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Log-amplitude variance and covariance of the scintillation of a diverging optical beam have been measured over a 48-hr period at a wavelength of 0.63[mu], on a 490 and 1000 m optical paths 2 m above the surface of a flat mesa near Boulder, Colorado. Simultaneous measurements of the refractive-index structure of the atmosphere have been obtained from temperature-structure-function measurements at spacings of 1, 3, and 10 cm. A saturation of scintillation occurs for values of log-amplitude variance between 0.5 and 1. After reaching a peak, the log-amplitude variance then decreases with both increasing range and increasing refractive-index turbulence. The spatial covariance of the fluctuations tends to increase in the saturation region. In the unsaturated region, the log-amplitude variance is approximately that predicted by the spherical-wave propagation theory of Tatarski.

Laser Beam Scintillation with Applications
Laser Beam Scintillation with Applications

Author: Larry C. Andrews

Publisher: SPIE Press

Published: 2001

Total Pages: 408

ISBN-13: 9780819441034

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Renewed interest in laser communication systems has sparked development of useful new analytic models. This book discusses optical scintillation and its impact on system performance in free-space optical communication and laser radar applications, with a detailed look at propagation phenomena and the role of scintillation on system behavior. Intended for practicing engineers, scientists, and students.

Airborne Laser Beam Propagation Measurements of High-Altitude Atmospheric Turbulence
Airborne Laser Beam Propagation Measurements of High-Altitude Atmospheric Turbulence

Author: Glen J. Morris

Publisher:

Published: 1972

Total Pages: 62

ISBN-13:

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Two NC-135 jet aircraft were used in an airborne laser beam scintillation experiment in order to measure high-altitude values of the index of refraction structure. Measurements were made for transmitter-receiver spacings of 0.5, 1.5, 2.0, and 3.0 km. Altitude values ranged from 1.5 km to 10.5 km in approximately 1.5 km increments. Measurements were made at optical wavelengths of 0.6328 micrometers and 10.6 micrometers. Computed scintillation parameters include log-intensity variance, probability distribution function, cumulative probability, and temporal power spectral density. Measured values of index of refraction structure were consistently higher than expected at high altitudes. Some contributions to the measured values of index of refraction structure may have come from boundary layer turbulence near the transmitting aircraft. However, this contribution is small. On the average, the upper atmosphere is much more turbulent than current models predict it to be.

Characterization of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons
Characterization of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons

Author:

Publisher:

Published: 2010

Total Pages: 13

ISBN-13:

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We describe preliminary results of a set of laser beam propagation experiments performed over a long (149 km) near-horizontal propagation path between Mauna Loa (Hawaii Island) and Haleakala (Island of Maui) mountains in February 2010. The distinctive feature of the experimental campaign referred to here as the Coherent Multi-Beam Atmospheric Transceiver (COMBAT) experiments is that the measurements of the atmospheric-turbulence induced laser beam intensity scintillations at the receiver telescope aperture were obtained simultaneously using three laser sources (laser beacons) with different wavelengths. The presented experimental results on intensity scintillation characteristics reveal complexity of the observed phenomena that cannot be fully explained based on the existing atmospheric turbulence models.