Propagation of High-Power Laser Radiation under Conditions  of Adaptive Control

doi:10.1117/3.2570042.ch7

Propagation of High-Power Laser Radiation under Conditions of Adaptive Control

Book: Atmospheric Adaptive Optics

Editor(s): Vladimir P. Lukin

Published: 1996

https://doi.org/10.1117/3.2570042.ch7

Abstract

The present chapter presents results of a numerical modeling study of possible ways of increasing the efficiency of coherent optical systems. We consider algorithms of phase correction of coherent adaptive optical systems based on the principle of phase co:rtjugation of a reference wave, with the aim of assessing the limits of their efficiency when used to transmit laser energy through the atmosphere. A study is presented of the extent to which such systems can suppress thermal distortions of laser beams of continuous radiation propagating through a moving, weakly absorbing, regular (or "frozen" random inhomogeneous) medium. The functioning of coherent optical systems in the atmosphere is accompanied by various kinds of noise: absorption and scattering by air molecules and aerosols, regular and random refraction of rays by turbulent fluctuations of the amplitude and phase of the optical wave, and self-induced thermal distortions of high-power laser beams. Some of these types of noise lead to irretrievable energy losses and can be minimized only by a corresponding ("optimal") choice of the parameters of the optical system, such as wavelength, power, pulse duration, aperture diameter, and focusing parameter. Other types of noise lead to a redistribution of the field energy over the cross section of the beam and can in principle be eliminated with the help of sufficiently fast adaptive control of both the amplitude and phase of the radiated wave.