Intensity fluctuations of reflected wave from distributed particles illuminated by a laser beam in atmospheric turbulence

Abstract

The intensity fluctuation of the reflected field from a group of discrete particles illuminated by a laser beam in turbulent atmosphere is investigated here. First, the expression of the correlation function of the received intensity is derived by dividing the illuminated space into a number of sub blocks. Then, the log-amplitude covariance function of the reflected waves from two particles at different heights in a turbulent atmosphere is deduced using the Rytov method. The dimensions of the sub blocks are discussed based on the 3D log-amplitude covariance function, and the normalized variance of the received intensity is calculated and discussed based on the sub blocks. Results show that the normalized variance is mainly affected by the cross section area of the illuminated space, whereas the latter is greatly influenced by the position of the received point and the width of the transmitting beam.