3. Infrared camera

We've just seen that the atmosphere has three transmission windows in the infrared, and it's in these wavelength bands that detectors are optimized.

We have at our disposal devices of varying complexity for imaging in IR bands I, II and III. Let's just say that the first cameras used a single detector associated with a two-axis mirror scanning device (rows and columns), then arrays were produced (a single scanning axis along the rows), and today we have cameras using detector arrays. It should be added here that detectors can be quantum, in which case they are cooled to eliminate the dark current, or thermal, like micro-bolometer arrays, which are not cooled.