Fluctuations of the parameters of an optical beam along a path with reflection in a turbulent atmosphere

The approximate smooth perturbation method is used to calculate the correlation functions of fluctuations in the phase, angles of arrival, amplitude levels, and variance of random displacements of the center of gravity of a Gaussian beam undergoing reflection in a randomly inhomogeneous medium. An ideal plane mirror, a 90° prism, and corner-cube and mirror-lens reflectors are considered as reflecting devices. The variance of the displacements of the center of gravity of the lidar reflector image in the focal plane of the receiving objective matched to the transmitting aperture is also studied. A comparison is made with similar characteristics for the field of a beam along a rectilinear path which is twice the distance between the transmitter-receiver and the reflector. It is found that "amplification" and "self-compensation" of fluctuations in the reflected beam parameters observed for various combinations of reflector and wavefront curvature in the geometric-optics approximation are smoothed out as the role of diffraction effects at the transmitter aperture and of inhomogeneities in the medium increases.