Experiments for Laser Beam Propagation Through Optical Turbulence

Experiments for Laser Beam Propagation Through Optical Turbulence
Author: Angel Fernandez
Publisher:
Total Pages: 0
Release: 2016
Genre:
ISBN:

Download Experiments for Laser Beam Propagation Through Optical Turbulence Book in PDF, Epub and Kindle

Atmospheric turbulence, generated by a differential temperature between the Earth's surface and the atmosphere, causes effects on optical waves that have been of great interest to scientists for many years. Wave front distortions in the optical wave induced by atmospheric turbulence result in a spreading of the beam beyond that due to pure diffraction, random variations of the position of the beam centroid, and a random redistribution of the beam energy within a cross section of the beam leading to irradiance fluctuations. Those effects have far-reaching consequences on astronomical imaging, free space optics (FSO) communications, remote sensing, laser satellite communication, astronomical imaging, adaptive optics, target designation, hyperspectral LiDAR, and other applications that require the transmission of optical waves through the atmosphere. Throughout this thesis, we introduce a globally concept of turbulence, focusing in atmospheric turbulence.Diverse experiments have been carried out, for instance, the propagation of two parallel thin beams under geometrical optics condition for studying the parameters of optical turbulence, and besides, the same optical configuration was used to investigate the best sampling rate for optical turbulence. Furthermore, we have measured evapotranspiration by remote sensing, in which we have heeded the fluctuations of the refractive index through the intensities of the turbulence. Finally, experiments which involve a new beam are also developed, such as phase-flipped Gaussian beam. This beam shows an experimental reduction on its irradiance fluctuations induced by the turbulence, which means that it has a high performance in optical communications. The experimental reduction aforementioned is proved through the comparison with the theory developed.

Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Experimental Investigations of Optical Propagation in Atmospheric Turbulence
Author: Michael W. Fitzmaurice
Publisher:
Total Pages: 196
Release: 1971
Genre: Atmospheric chemistry
ISBN:

Download Experimental Investigations of Optical Propagation in Atmospheric Turbulence Book in PDF, Epub and Kindle

The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.

Optical Waves and Laser Beams in the Irregular Atmosphere

Optical Waves and Laser Beams in the Irregular Atmosphere
Author: Nathan Blaunstein
Publisher: CRC Press
Total Pages: 314
Release: 2017-09-22
Genre: Computers
ISBN: 1351402676

Download Optical Waves and Laser Beams in the Irregular Atmosphere Book in PDF, Epub and Kindle

The book introduces optical wave propagation in the irregular turbulent atmosphere and the relations to laser beam and LIDAR applications for both optical communication and imaging. It examines atmosphere fundamentals, structure, and content. It explains specific situations occurring in the irregular atmosphere and for specific natural phenomena that affect optical ray and laser beam propagation. It emphasizes how to use LIDAR to investigate atmospheric phenomena and predict primary parameters of the irregular turbulent atmosphere and suggests what kinds of optical devices to operate in different atmospheric situations to minimize the deleterious effects of natural atmospheric phenomena.

Laser Beam Propagation Through Random Media

Laser Beam Propagation Through Random Media
Author: Larry C. Andrews
Publisher: SPIE-International Society for Optical Engineering
Total Pages: 506
Release: 1998
Genre: Science
ISBN:

Download Laser Beam Propagation Through Random Media Book in PDF, Epub and Kindle

Very Good,No Highlights or Markup,all pages are intact.

Laser Beam Propagation in the Atmosphere

Laser Beam Propagation in the Atmosphere
Author: J. W. Strohbehn
Publisher: Springer
Total Pages: 328
Release: 2014-03-12
Genre: Technology & Engineering
ISBN: 9783662311615

Download Laser Beam Propagation in the Atmosphere Book in PDF, Epub and Kindle

With contributions by numerous experts

Numerical/Optical Simulation of Laser Beam Propagation Through Atmospheric Turbulence

Numerical/Optical Simulation of Laser Beam Propagation Through Atmospheric Turbulence
Author:
Publisher:
Total Pages: 76
Release: 1995
Genre:
ISBN:

Download Numerical/Optical Simulation of Laser Beam Propagation Through Atmospheric Turbulence Book in PDF, Epub and Kindle

In this project, computer simulation and optical modeling of laser beam propagation through the turbulent atmosphere, as well as development of techniques using photorefractive crystals to mitigate phase distortions in laser beams, have been done. In the framework of the first direction the mathematical methods and computational schemes based on split step operators, phase screen model and the Monte Carlo method have been elaborated. Spatial statistics of light field in laser beam has been studied in relation to inner and outer scales for different models of atmospheric turbulence. Regimes of weak, moderate and strong fluctuations have been considered. In the framework of the second direction the possibility of simulation of double pass and anisoplanatic effects by means of few phase screens has been studied. An experimental set up for optical modeling anisoplanatic effects by the use of dynamic phase modulator has been designed. A method of generation of random optical field with variable correlation function has been proposed and tested. In the framework of the third direction the problem of mitigation of distorted optical signals in photorefractive crystals has been studied. An optimal effective operating range of one way system, based on nonlinear interaction of distorted signal with pumping formed by spatial filtering of the signal, has been found. Using the criterion of maximal mitigation of phase and amplitude distortions, the schemes of two and four beam interaction in InP:Fe have been optimized.

Optical Beam Propagation in Turbulent Media

Optical Beam Propagation in Turbulent Media
Author: Ronald Louis Fante
Publisher:
Total Pages: 88
Release: 1975
Genre: Atmospheric turbulence
ISBN:

Download Optical Beam Propagation in Turbulent Media Book in PDF, Epub and Kindle

The most recent developments on the propagation of microwave and optical beams in turbulent media, such as the clear atmosphere are discussed. Among the phenomena considered are beam spreading, beam wander, loss of coherence, scintillations, angle-of-arrival variations, and short pulse effects. Also included is a discussion of methods of compensation of the effect of turbulence on communications and imaging systems.

Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Experimental Investigations of Optical Propagation in Atmospheric Turbulence
Author: Michael W. Fitzmaurice
Publisher:
Total Pages: 196
Release: 1971
Genre: Atmospheric chemistry
ISBN:

Download Experimental Investigations of Optical Propagation in Atmospheric Turbulence Book in PDF, Epub and Kindle

The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.