Sun Xiaoli
Planetary Geology, Geophysics and Geochemistry Laboratory, Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
Sensors (Basel). 2024 Oct 14;24(20):6620. doi: 10.3390/s24206620.
Photodetectors play a critical role in space lidars designed for scientific investigations from orbit around planetary bodies. The detectors must be highly sensitive due to the long range of measurements and tight constraints on the size, weight, and power of the instrument. The detectors must also be space radiation tolerant over multi-year mission lifetimes with no significant performance degradation. Early space lidars used diode-pumped Nd:YAG lasers with a single beam for range and atmospheric backscattering measurements at 1064 nm or its frequency harmonics. The photodetectors used were single-element photomultiplier tubes and infrared performance-enhanced silicon avalanche photodiodes. Space lidars have advanced to multiple beams for surface topographic mapping and active infrared spectroscopic measurements of atmospheric species and surface composition, which demand increased performance and new capabilities for lidar detectors. Higher sensitivity detectors are required so that multi-beam and multi-wavelength measurements can be performed without increasing the laser and instrument power. Pixelated photodetectors are needed so that a single detector assembly can be used for simultaneous multi-channel measurements. Photon-counting photodetectors are needed for active spectroscopy measurements from short-wave infrared to mid-wave infrared. HgCdTe avalanche photodiode arrays have emerged recently as a promising technology to fill these needs. This paper gives a review of the photodetectors used in past and present lidars and the development and outlook of HgCdTe APD arrays for future space lidars.
光电探测器在为围绕行星体轨道进行科学研究而设计的空间激光雷达中起着关键作用。由于测量距离长以及对仪器尺寸、重量和功率的严格限制，探测器必须具有高灵敏度。探测器还必须在多年任务寿命期间耐受空间辐射，且性能无显著下降。早期的空间激光雷达使用二极管泵浦的Nd:YAG激光器，通过单束光在1064 nm或其频率谐波下进行距离和大气后向散射测量。所使用的光电探测器是单元素光电倍增管和红外性能增强的硅雪崩光电二极管。空间激光雷达已发展到使用多束光进行表面地形测绘以及对大气成分和表面组成进行主动红外光谱测量，这对激光雷达探测器的性能和新功能提出了更高要求。需要更高灵敏度的探测器，以便在不增加激光和仪器功率的情况下进行多光束和多波长测量。需要像素化光电探测器，以便单个探测器组件可用于同时进行多通道测量。从短波红外到中波红外的主动光谱测量需要光子计数光电探测器。HgCdTe雪崩光电二极管阵列最近已成为满足这些需求的一项有前景的技术。本文综述了过去和现在的激光雷达中使用的光电探测器以及用于未来空间激光雷达的HgCdTe APD阵列的发展和前景。
