Researchers have designed a single-photon time-of-flight LiDAR system that can acquire a high-resolution 3D image of an object or scene up to 1 kilometer away. The new system could help enhance security, monitoring, and remote sensing by enabling detailed imaging even in challenging environmental conditions or when objects are obscured by foliage or camouflage netting.
So, keep in mind that single photon sensors have been around for awhile, in the form of avalanche photodiodes and photomultiplier tubes. And avalanche photodiodes are pretty commonly used in LiDAR systems already.
The ones talked about in the article I linked collect about 50 points per square meter at a horizontal resolution of about 23 cm. Obviously that’s way worse than what’s presented in the phys.org article, but that’s also measuring from 3km away while covering an area of 700 square km per hour (because these systems are used for wide area terrain scanning from airplanes). With the way LiDAR works the system in the phys.org article could be scanning with a very narrow beam to get way more datapoints per square meter.
Now, this doesn’t mean that the system is useless crap or whatever. It could be that the superconducting nanowire sensor they’re using lets them measure the arrival time much more precisely than normal LiDAR systems, which would give them much better depth resolution. Or it could be that the sensor has much less noise (false photon detections) than the commonly used avalanche diodes. I didn’t read the actual paper, and honestly I don’t know enough about LiDAR and photon detectors to really be able to compare those stats.
But I do know enough to say that the range and single-photon capability of this system aren’t really the special parts of it, if it’s special at all.