{{Short description|Detector that reacts to infrared (IR) radiation}} {{More citations needed|date=June 2012}} [[File:RAPID A High-speed Infrared Detector.jpg|thumb|300px|Prototype of high-speed infrared detector installed on the PIONIER instrument at ESO’s Paranal Observatory.<ref>{{cite web|title=Revolutionary New High-speed Infrared Detector Sees First Light|url=http://www.eso.org/public/announcements/ann15042/|access-date=15 June 2015}}</ref>]] An '''infrared detector''' is a detector that reacts to infrared (IR) radiation. The two main types of detectors are thermal and photonic (photodetectors).
The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena.<ref name="SC">{{cite journal|journal=Micromachines|year=2022|first1=M.|last1=Avraham|first2=J.|last2=Nemirovsky|first3=T.|last3=Blank|first4=G.|last4=Golan|first5=Y.|last5=Nemirovsky|title=Toward an Accurate IR Remote Sensing of Body Temperature Radiometer Based on a Novel IR Sensing System Dubbed Digital TMOS|volume = 13|number = 5|page=703 |doi = 10.3390/mi13050703|pmid=35630174 |pmc=9145132 |doi-access=free}}</ref> Bolometers and microbolometers are based on changes in resistance. Thermocouples and thermopiles use the thermoelectric effect. Golay cells follow thermal expansion. In IR spectrometers 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 are semiconductors with narrow band gaps. Incident IR photons can cause electronic excitations. In photoconductive detectors, the resistivity of the detector element is monitored. Photovoltaic detectors contain a p-n junction on which photoelectric current appears upon illumination.
An infrared detector is hybridized by connecting it to a readout integrated circuit with indium bumps. This hybrid is known as a focal plane array.
==Detector materials== The materials basis for infrared detection devices are narrow-gap semiconductors, including compounds and alloys of bismuth, antimony, indium, cadmium, selenium and others.<ref>{{cite journal|title=Narrwo-Bandgap Materials for Optoelectronics Applications|first1=Xiao-Hui|last1=Li|date=2022|doi=10.1007/s11467-021-1055-z|url=https://link.springer.com/article/10.1007/s11467-021-1055-z|volume=17|article-number=13304|journal=Frontiers of Physics|issue=1 |bibcode=2022FrPhy..1713304L |s2cid=237652629 |url-access=subscription}}</ref><ref>{{cite book|title=Physics and Properties of Narrow Gap Semiconductors|url=https://link.springer.com/book/10.1007/978-0-387-74801-6|first1=Junhao|last1=Chu|first2=Arden|last2=Sher|date=2008 |publisher=Springer|doi=10.1007/978-0-387-74801-6 | isbn=9780387747439}}</ref>
* Lead(II) sulfide (PbS) * Mercury cadmium telluride (Known as MCT, HgCdTe) * Indium antimonide (InSb) * Indium arsenide * Indium gallium arsenide * Lead selenide * QWIP * Lithium tantalate (LiTaO<sub>3</sub>) * Triglycine sulfate (TGS) * Platinum silicide (PtSi)
==See also== * Infrared imaging
==References== {{reflist}}
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Category:Detectors Category:Image sensors Category:Infrared imaging