- Infrared detector
An infrared detector is a
photodetector that reacts toinfrared (IR)radiation . The two main types of detectors are thermal and photonic.The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena.
Bolometer s andmicrobolometer s are based on changes in resistance.Thermocouple s andthermopile s use thethermoelectric effect . Golay cells follow thermal expansion. In IRspectrometer s the pyroelectric detectors are the most widespread.The response time and sensitivity of photonic detectors can be much higher, but usually these have to be cooled to cut
thermal noise . The materials in these aresemiconductors with narrow band gaps. Incident IR photons can cause electronic excitations. Inphotoconductive detectors, theresistivity of the detector element is monitored.Photovoltaic detectors contain ap-n junction on which photoelectric current appears upon illumination.A few detector materials:Types
Vanadium pentoxide is frequently used as a detector material in uncooledmicrobolometer arrays.External links
* [http://sales.hamamatsu.com/assets/applications/SSD/Characteristics_and_use_of_infrared_detectors.pdf Characteristics and Use of Infrared Detectors] Hamamatsu Photonics
* [http://sales.hamamatsu.com/assets/applications/SSD/irdetectorvariety.pdf Technological Advances Lead to Greater Variety of Infrared Detectors] Hamamatsu PhotonicsconclusionTHERMOCOUPLE-Di similar stripes of metals,BOLOMETER- Metal or semiconductor,THERMISTOR-Metallic oxide(not used in open environment),GOLAY CELL - Black metal plates (commercially used)
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