February 2024
Spotlight Summary by Daniele Faccio
Non-line-of-sight imaging at infrared wavelengths using a superconducting nanowire single-photon detector
Feng et al. report on the use of a large area “fractal” superconducting nanowire single photon detector (SNSPD) to reconstruct 3D images of a scene behind a wall at wavelengths between 1500 and 1900 nm. In this spectral region, sun irradiance is significantly lower compared to more traditional wavelengths, thus promising high precision, non-line-of-sight imaging in real-world scenes.
The team uses a new generation SNSPD sensor that has a large area and is relatively insensitive to polarisation. They can then capture the remaining photons from a laser beam that is reflected from a surface, bounces behind a wall that is hiding a scene, from which photons are then retro-reflected back by the same path to the SNSPD sensor. The three-dimensional image of the hidden objects is reconstructed numerically from the time-of-flight data of the detected photons.
The SNSPD have a very high temporal resolution and this in turn allows to image objects beyond the line of sight with a transverse resolution of 1-2 cm. The detectors also have high sensitivity out to relatively long wavelengths in the 2 micrometer region. Estimations by the team indicate that the lower quantum efficiency at longer wavelengths is offset by the even lower solar radiation, thus resulting in an improved signal-to-noise ratio.
Despite the detector technology requiring cryo-cooling, advances towards miniaturisation and portability hold promise for future systems that could be deployed in the real-world for non-line-of-sight imaging.
You must log in to add comments.
The team uses a new generation SNSPD sensor that has a large area and is relatively insensitive to polarisation. They can then capture the remaining photons from a laser beam that is reflected from a surface, bounces behind a wall that is hiding a scene, from which photons are then retro-reflected back by the same path to the SNSPD sensor. The three-dimensional image of the hidden objects is reconstructed numerically from the time-of-flight data of the detected photons.
The SNSPD have a very high temporal resolution and this in turn allows to image objects beyond the line of sight with a transverse resolution of 1-2 cm. The detectors also have high sensitivity out to relatively long wavelengths in the 2 micrometer region. Estimations by the team indicate that the lower quantum efficiency at longer wavelengths is offset by the even lower solar radiation, thus resulting in an improved signal-to-noise ratio.
Despite the detector technology requiring cryo-cooling, advances towards miniaturisation and portability hold promise for future systems that could be deployed in the real-world for non-line-of-sight imaging.
Add Comment
You must log in to add comments.
Article Information
Non-line-of-sight imaging at infrared wavelengths using a superconducting nanowire single-photon detector
Yifan Feng, Xingyu Cui, Yun Meng, Xiangjun Yin, Kai Zou, Zifan Hao, Jingyu Yang, and Xiaolong Hu
Opt. Express 31(25) 42240-42254 (2023) View: HTML | PDF