Monte Carlo simulation of polarization of light back-scattered from randomly rough surfaces

Laser detection devices obtain target information from back-scattered light, such as lidar. The rec-ognition rate can be improved by analyzing intensity and polarization of echo signal. In this paper, Monte Carlo method is used to generate a large number of randomly rough surfaces to simulate targets. Every rough surface is discretized into a large number of micro-surface elements. Stokes parameters of back-scattered light are calculated by numerical integration. Incident light is p-, s-, 45 degrees linearly polarized light and right-hand circularly polarized light, respectively. Numerical re-sults show that when s-and p-linearly polarized light incident on a metal rough surface, back -scat-tered light appears circularly polarized component. Metal rough surface resembles a wave plate with phase difference, with the fast axis parallel or perpendicular to the 45 degrees direction. When linearly polarized light is incident on dielectric rough surface, back-scattered light has no circularly polar-ized component. Experimental data are consistent with the numerical results. The above research provides a new basis for laser detection device to identify metal targets from the environmental background.