High resolution stimulated Brillouin scattering lidar using Galilean focusing system for detecting submerged objects

To improve the performance of stimulated Brillouin scattering (SBS) lidar system, a new focusing system based on Galilean telescope was designed, and the influences of focusing system on the resolution of SBS lidar were investigated theoretically and experimentally. The experiments for real-time detecting submerged object were carried out in a 100 m-long water pool. The results indicate that the focusing system can improve greatly the resolution of SBS lidar system to 0.1 m at the detecting distance of 5 m, and less than 0.5 m within the detection distances of 30 m. The attenuation coefficient of water was 0.38 m−1, and the detection distance of SBS lidar in this experiment exceeds 11 attenuation lengths. The experimental results agree well with the theoretical simulations.