Accession Number : ADA311320

Title :   Numerical/Optical Simulation of Laser Beam Propagation Through Atmospheric Turbulence.

Descriptive Note : Final rept. 1 Oct 94-1 Dec 95,

Corporate Author : MOSCOW STATE UNIV (USSR)

Personal Author(s) : Chesnokov, Sergei S. ; Kandidov, Valerii P. ; Shmalhausen, Victor I. ; Shuvalov, Vladimir V.

PDF Url : ADA311320

Report Date : 01 DEC 1995

Pagination or Media Count : 76

Abstract : 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.

Descriptors :   *LASER BEAMS, *PHOTOREFRACTIVE MATERIALS, *DISTORTION, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, SPATIAL DISTRIBUTION, OPTICAL PROPERTIES, NUMERICAL ANALYSIS, TURBULENCE, ATMOSPHERIC MOTION, MONTE CARLO METHOD, CORRELATION, SCALE, LIGHT TRANSMISSION, RUSSIA, MODULATORS, PHASE MODULATION.

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE