# Single-photon imaging over 200 km

arXiv: https://arxiv.org/abs/2103.05860 · HTML: https://mlsanity.com/paper/2103.05860/

## Key facts

- Cited by 10 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 10 Mar 2021.

## Built on by (most cited first, 10 of 10)

- [Recent Advances on Non-Line-of-Sight Imaging: Conventional Physical Models, Deep Learning, and New Scenes](https://mlsanity.com/paper/2104.13807/) (2021)
- [High-speed object detection with a single-photon time-of-flight image sensor](https://mlsanity.com/paper/2107.13407/) (2021)
- [Single-photon Image Super-resolution via Self-supervised Learning](https://mlsanity.com/paper/2303.02033/) (2023)
- [Single-pixel 3D imaging based on fusion temporal data of single photon detector and millimeter-wave radar](https://mlsanity.com/paper/2312.12439/) (2023)
- [Simulating single-photon detector array sensors for depth imaging](https://mlsanity.com/paper/2210.05644/) (2022)
- [Scattering-induced entropy boost for highly-compressed optical sensing and encryption](https://mlsanity.com/paper/2301.06084/) (2022)
- [Long-Distance Field Demonstration of Imaging-Free Drone Identification in Intracity Environments](https://mlsanity.com/paper/2504.20097/) (2025)
- [Toward Robust Single-Photon Perception for Robots: A Condition-Aware Active Learning Approach](https://mlsanity.com/paper/2505.04376/) (2025)
- [Point upsampling networks for single-photon sensing](https://mlsanity.com/paper/2508.12986/) (2025)
- [3D Reconstruction from Transient Measurements with Time-Resolved Transformer](https://mlsanity.com/paper/2510.09205/) (2025)

## Abstract (arXiv)

Long-range active imaging has widespread applications in remote sensing and target recognition. Single-photon light detection and ranging (lidar) has been shown to have high sensitivity and temporal resolution. On the application front, however, the operating range of practical single-photon lidar systems is limited to about tens of kilometers over the Earth's atmosphere, mainly due to the weak echo signal mixed with high background noise. Here, we present a compact coaxial single-photon lidar system capable of realizing 3D imaging at up to 201.5 km. It is achieved by using high-efficiency optical devices for collection and detection, and what we believe is a new noise-suppression technique that is efficient for long-range applications. We show that photon-efficient computational algorithms enable accurate 3D imaging over hundreds of kilometers with as few as 0.44 signal photons per pixel. The results represent a significant step toward practical, low-power lidar over extra-long ranges.