A conventional thermal camera is like a thermometer that slowly heats up and cools down. It shows where heat is well, but it can't keep up with fast motion. The new sensor works differently: it counts individual quanta of heat, like a droplet counter during rain.
Inside the sensor is a thin layer that changes its magnetic properties when infrared light hits it. These changes occur randomly and in jumps. Each jump is one event, one 'drop strike.' The sensor doesn't wait for the whole material to warm up; it registers each such jump immediately.
This approach doesn't require bulky liquid nitrogen cooling, which many infrared cameras need. The sensor operates at ordinary temperature and consumes just 0.2 microwatts per pixel — less than an LED in a TV.
Heat can now be seen as a stream of fast events, not as a blurry image. This opens the door to compact and economical thermal cameras for drones, robots, and security systems.
The sensor detects heat by counting random magnetic jumps — much like a Geiger counter counts radioactive particles.