In this paper, an improved semi-analytic Monte Carlo method is used to simulate the lidar received backscattering signals. The H-G function is used to approximate the scattering phase function of seawater, from which we can derive the scattering angle directly, and a modified H-G function is used to calculate the probability of the photons received by the receiver at each scattering point, which greatly improves the accuracy of the simulation. The simulation result shows that the different parameters of air-sea system of lidar, such as lidar’s field of view, attenuation coefficient and single scattering albedo of seawater, greatly influence the lidar received backscattering signal waveform. Multiple scattering is studied to explain these phenomena.
This paper describes a new approach for flattening high-power and high-gain CO2 lasers. A periodic change of curvature of concave mirror causes beam modes to jump in the course of time. Averaging out these beams results in an intensity profile with good uniformity. It is also compared to the output intensity ofthe resonator without vibration.