IR-detectors inside a TO- or BNC-cover
IR-detectors with a four-stage cooling
PEM-detector, time constant ca. 0.2 ns
Explanation to the VIGO IR-detector program
In relation to the used materials the detectors are subdivided
- HgCdTe (often abbreviated as MCT)
- InAs and InAsSb-Detectors
According to the classification of the semiconductors in the periodic table of the elements one speaks about detectors from II-VI-semiconductors (Hg, Cd, Te) and III-V-semiconductors (In, As, Sb)
In relation to the functional principle the detectors can be divided into three groups
- PV – Photo-Voltaic
- PEM – Photo-Electro-Magnetic
- PC – Photo Conductor
In relation to the cooling the detectors are divided into two groups, the room temperature detectors and the detectors with a 2, 3 or 4 stage thermoelectric cooling (named with 2TE, 3TE or 4TE)
In addition the letters „M“ and „I“ are used in the detector types.
M for Multiple Junction: A multiple of serial p-n-transitions increases the responsivity of the detectors and make it possible to produce long wave length detectors with larger areas.
I for optical Immersion: The principle of optical immersion decreases the electric area in relation to the optical area with resulting improved noise parameter of the detector
Uncooled detectors are standardly delivered without windows, though it is recommended for rough, dusty environment to consider a window.
TE cooled detectors need implicitly for the protection against icing a window.
All windows possess a 3°-wedge to surpress interferences (fringin).
ZnSe is supplied with an AR-coating, for sapphire it is an option. BaF2-Fenster stays without AR.
Uncooled IR Detectors
TE cooled IR Detectors
Photovoltaic Infrared-Detectors made from HgCdTe