Thermal self-action of high-power continuous and pulse-periodic CO2 laser radiation in air: I. Numerical simulation of propagation along an atmospheric path

Abstract

A problem of transportation of high-power laser radiation energy at a wavelength of 10.6 μm in the atmosphere is theoretically considered in terms of its thermal and wind nonlinearities. The power characteristics of continuous and pulse-periodic radiation are studied during propagation along a surface kilometer-long atmospheric path with sharp focusing onto a receiver. Key factors most affecting high-power radiation propagation are found. It is ascertained that an undesirable effect of thermal defocusing can be reduced using a train of low-power short pulses with a quite high repetition rate due to the effect of light-induced “blooming” of the gas medium. The questions of scaling optical paths from the viewpoint of their equivalence in manifestation of thermal nonlinearity are discussed.