Infrared detector module for airborne hyperspectral LiDAR: design and demonstration

Realizing the integrated acquisition and identification of the elevation information and spectral information of the observation target is at the frontier and a future trend of Earth observation technology. This study designs and develops a set of airborne hyperspectral imaging lidar optical receiving systems and investigates the detection of the infrared band echo signal of the lidar system. A set of avalanche photodiode (APD) detectors is independently designed to detect the weak echo signal of  800-900 nm band. The actual radius of the photosensitive surface of the APD detector is 0.25 mm. We design and demonstrate the optical focusing system of the APD detector in the laboratory and obtain that the image plane size of the optical fiber end faces of the APD detector from channel 47 to channel 56 is close to 0.3 mm. Results show that the optical focusing system of the self-designed APD detector is reliable. On the basis of the focal plane splitting technology of the fiber array, we couple the echo signal of  800-900 nm band to the corresponding APD detector through the fiber array and conduct a series of test experiments for the APD detector. Field test results of the ground-based platform show that the APD detectors in all channels can complete the remote sensing measurement of 500 m. The development of this APD detector solves the problem of hyperspectral imaging under weak light signals and realizes the accurate detection of ground targets in the infrared band by airborne hyperspectral imaging lidar.