REFLECTION OF A NONSTATIONARY BEAM OF LIGHT FROM AN ABSORBING MEDIUM IN THE CASE OF GRAZING-INCIDENCE

Temporal characteristics of the reflected radiation intensity in the c ase of a nonstationary light beam incident at grazing angles upon a se mi-infinite medium with large-scale scattering centers are investigate d. The problem of small-angle Light reflection is solved within the Fo kker-Planck approximation. An analytical expression for the reflected radiation intensity is obtained. Temporal characteristics of the refle cted radiation are investigated in detail for the most important cases of incident beam modulation: delta pulse, a sequence of rectangular p ulses of different duty factors, and a harmonically modulated light si gnal. The transition mode for different grazing angles and parameters of the scattering medium has been investigated explicitly. Thus, for e xample, the characteristic transition time to the stationary mode is c alculated for irradiation of the medium with a steplike light pulse.