Upconversion imaging through scattering media in noisy environments

Imaging through strongly scattering media in noisy environments is full of challenges. To address this issue, we present an imager based on an upconversion single-photon detector. This upconversion detector shows superior noise tolerance due to sharp optical time gating, quantum mode selectivity, and parametric frequency upconversion. To demonstrate the noise tolerance of the system, we experimentally compared the performance of a near-infrared detector and an upconversion detector, focusing on the influences of integration time, noise intensity, and object surface type on imaging quality. Experimental results show that, compared with the near-infrared detector, the upconversion detector exhibits superior robustness in high-noise environments, capable of obtaining clear images through strongly scattering media with optical thickness up to 12 l s and a signal-to-noise ratio of 1/400.