Single-photon laser reflective tomography over 7 km

Long-range, high-resolution imaging is valuable in a variety of applications, including space debris monitoring or Earth observation. While traditional imaging techniques have limited lateral resolution due to optical diffraction, laser reflective tomography (LRT) can surpass the limit and reconstruct the three-dimensional image of objects by measuring the one-dimensional range profiles of the objects from different angles. The independence of spatial resolution and the long-range imaging capability makes this a strong candidate technology for optical remote sensing applications. The present study describes a compact high performance time-correlated single-photon counting (TCSPC) range profiling system. With the proposed computational reconstruction framework, experimental results of laser reflective tomography at 7.1 km ranges with 1.2 cm resolution are presented, which is roughly 30-times better resolution than optical diffraction limit. Accurate 3D tomography of complex objects is also verified in this work. The results indicate the great potential for practical, compact, high-resolution imaging systems over extra-long ranges.