激光雷达在海洋遥感、测绘及监测等应用中具有重要前景。海面由于各种因素总存在一定粗糙度,影响水下激光穿过海气界面后的光学特性,导致出射光束漂移和光斑畸变,使得出射光场分布特性复杂,成为制约激光在海洋环境上下行有效传输的重要问题。为了分析海气界面对激光传输的影响,基于几何光学理论分析、三维海浪模拟和蒙特卡罗仿真,并辅以水池观测实验加以验证,对水下向上传输激光束通过海气界面的出射光场分布特性进行研究。结果表明,在上行准直激光束垂直向上发射的情况下,光束主要集中在中心指向±10°范围以内,通过采用合理的发射方式和设置适当的技术参数,将可以在一定程度上减弱海气界面的影响,促进激光在海洋相关领域的实际应用。

Lidar has been used for ocean remote sensing widely. The upward laser beam is distorted due to the rough sea surface. It limits dramatically laser transmission through sea surface and the application of Lidar under water. The beam distribution of upward laser beam through sea surface is studied based on the geometric optical theory,three dimension wave simulation and Monte Carlo simulation respectively. Results show similar beam distribution by the three methods. The beam profile is limited in ±10° for collimated vertical upward beam. Demonstration of beam distribution through man-made rough water surface is conducted in a water tank. Results show that the exit angle is actually limited within ±10°. The study will be useful to the design of Lidar application under sea water.