Shangguan Mingjia, Yang Zhifeng, Lin Zaifa, Weng Zhenwu, Sun Jiaxin
Opt Lett. 2024 Feb 1;49(3):626-629. doi: 10.1364/OL.514622.
A compact underwater lidar system, utilizing a single-photon detection technology, is proposed to effectively eliminate interference from the sea-air interface and enhance the accuracy of water optical property measurements. However, the high sensitivity of the single-photon detector poses challenges, including daytime operation difficulties due to strong solar radiation noise and detector saturation from near-field lidar signals. To address these issues, the laser and optical receiver of the lidar are optimized to suppress solar radiation noise, and a dual-telescope structure is introduced to improve the dynamic measurement range beyond 70 dB. In addition, a Monte Carlo simulation establishes the relationship between beam attenuation coefficients (c) and lidar attenuation coefficients (K), enabling the retrieval of c profiles from K. A field experiment conducted in the South China Sea, spanning from inshore to offshore waters, demonstrates the effectiveness of the lidar. The results highlight its potential applications, including the assessment of subsurface particulate organic carbon (POC).
提出了一种采用单光子探测技术的紧凑型水下激光雷达系统，以有效消除海气界面的干扰并提高水体光学特性测量的准确性。然而，单光子探测器的高灵敏度带来了挑战，包括由于强烈的太阳辐射噪声导致白天运行困难以及近场激光雷达信号使探测器饱和。为了解决这些问题，对激光雷达的激光器和光学接收器进行了优化以抑制太阳辐射噪声，并引入了双望远镜结构以将动态测量范围提高到70 dB以上。此外，通过蒙特卡洛模拟建立了光束衰减系数（c）与激光雷达衰减系数（K）之间的关系，从而能够从K中反演c剖面。在南海从近岸到近海海域进行的现场实验证明了该激光雷达的有效性。结果突出了其潜在应用，包括对表层以下颗粒有机碳（POC）的评估。
