Dual-wavelength 3D single-pixel imaging based on gated photon counting

We propose a compact dual-path single-pixel imaging (SPI) system based on gated photon counting for dual-wavelength three-dimensional depth imaging, under extremely low-light conditions. The system employs synchronized 1064 nm and 532 nm pulsed lasers as illumination sources, a spatial light modulator for structured detection, and a Geiger-mode avalanche photodetector. Leveraging gated detection, the system simultaneously performs two-dimensional slice imaging and time-of-flight depth imaging under both near-infrared (NIR) and visible (VIS) bands. Under sub-picowatt photon flux, the system achieves a spatial resolution of 2 mm and a longitudinal resolution of 12 cm, at a working distance of 1.5 m. Experimental results demonstrate that 64 × 64-pixel VIS and NIR images can be captured within approximately 1 s and 5 s, respectively. Compared with conventional photon-counting LiDAR or single-wavelength SPI systems, the proposed system offers improved photon efficiency and environmental adaptability. The NIR channel can also provide enhanced penetration in scattering media, while the VIS channel offers superior spatial resolution. The integration of the two channels is anticipated to significantly enhance imaging performance in complex scattering environments. This method can be further extended for spectral-depth imaging and polarization-depth imaging, and offers an efficient imaging solution for photon-starved environments, showing strong potential for applications in remote sensing, night vision imaging, quantum sensing, and target recognition.