Korotkova Olga, Avramov-Zamurovic Svetlana, Malek-Madani Reza, Nelson Charles
Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146, USA.
Opt Express. 2011 Oct 10;19(21):20322-31. doi: 10.1364/OE.19.020322.
A number of field experiments measuring the fluctuating intensity of a laser beam propagating along horizontal paths in the maritime environment is performed over sub-kilometer distances at the United States Naval Academy. Both above the ground and over the water links are explored. Two different detection schemes, one photographing the beam on a white board, and the other capturing the beam directly using a ccd sensor, gave consistent results. The probability density function (pdf) of the fluctuating intensity is reconstructed with the help of two theoretical models: the Gamma-Gamma and the Gamma-Laguerre, and compared with the intensity's histograms. It is found that the on-ground experimental results are in good agreement with theoretical predictions. The results obtained above the water paths lead to appreciable discrepancies, especially in the case of the Gamma-Gamma model. These discrepancies are attributed to the presence of the various scatterers along the path of the beam, such as water droplets, aerosols and other airborne particles. Our paper's main contribution is providing a methodology for computing the pdf function of the laser beam intensity in the maritime environment using field measurements.
在美国海军学院，进行了一系列实地实验，测量在海洋环境中沿水平路径传播的激光束的起伏强度，实验距离在亚公里范围内。研究了地面链路和水面链路。采用了两种不同的检测方案，一种是在白板上拍摄光束，另一种是直接使用电荷耦合器件（CCD）传感器捕获光束，两种方案得到了一致的结果。借助伽马-伽马（Gamma-Gamma）和伽马-拉盖尔（Gamma-Laguerre）这两种理论模型重建了起伏强度的概率密度函数（pdf），并与强度直方图进行了比较。发现地面实验结果与理论预测吻合良好。水面路径上获得的结果存在明显差异，特别是在伽马-伽马模型的情况下。这些差异归因于光束路径上存在各种散射体，如水滴、气溶胶和其他空气中的粒子。本文的主要贡献是提供了一种利用实地测量计算海洋环境中激光束强度pdf函数的方法。
