What is a microbolometer?

A bolometer is a very sensitive digital thermometer where its electrical resistance varies with temperature. A microbolometer is a specific type of bolometer used as a detector in a thermal camera.

It is a grid of microscopic vanadium oxide (or amorphous silicon) heat sensors atop a corresponding grid of silicon. Infrared radiation from a specific range of wavelengths strikes the VOx and changes its electrical resistance. This resistance change is measured and processed into temperatures which can be represented graphically.