High-Resolution Single-Photon Imaging with a Low-Fill-Factor 32 × 32 SPAD Array by Scanning in the Photosensitive Area

Single-photon light detection and ranging (LiDAR) provides the single-photon sensitivity and picosecond time resolution, which is rapidly developing in three-dimensional (3D) imaging applications. Spatial resolution and imaging quality of LiDAR based on the single-photon avalanche-diode (SPAD) array detectors are difficult to improve, because currently available SPAD arrays still have small size array, due to the semiconductor manufacturing process limitation, and the functional circuitry around pixels reduces the fill factor. Herein, we propose a photon-efficient LiDAR method that guarantees the coupling relationship between the photosensitive area of each pixel and the corresponding beam spot illuminated on the target and uses 1/4 field of view (FoV) scanning imaging in the photosensitive area. The proposed method can effectively improve the spatial resolution of LiDAR system based on SPAD array detectors. Resolution test experiments show that the best observed (transversal) resolution is 3.1748 lp/mm at a working distance of 2.3 m, over tenfold larger than that of previous methods. Three-dimensional experiments prove that the system can achieve 3D high-resolution single-photon imaging, which is valuable in the fields of remote sensing and long-range target recognition.