Bolometer

A bolometer is a device used to measure radiation based on a resistance thermometer. When radiation is absorbed, it causes heating on a surface that is as blackened as possible. This heating leads to a change in resistance in the material, which can be measured. Semiconductors (thermistors) are often used because their temperature coefficient is high, making the detector more sensitive. A thermal bridge with a defined thermal resistance to a heat sink of known temperature allows for continuous measurement of radiation. Nowadays, very thin coatings with a high absorption coefficient for a wide part of the electromagnetic spectrum can be produced, making bolometer detectors suitable for detecting infrared radiation over a wide spectral range. When multiple bolometers are combined to form an array, an imaging device for detecting infrared radiation, an infrared camera, can be built.