Detectors indium gallium arsenide

While most other techniques use a limited amount of detectors (e.g., silica for visible, photomultipliers for UV) and MIR has a small number, NIR uses many types of semiconductors for detectors. The original PbS detectors are still one of the largest used in NIR, however, indium gallium arsenide (InGaAs), indium arsenide (InAs), indium antimonide (InSb), and lead selenide (PbSe) are among the semiconductor combinations used, both cooled and ambient. 

Instead of glowbars, as used in MIR, tungsten halogen lamps are the sources of light. The detectors are solid-state semiconductors such as lead sulfide (PbS) or indium gallium arsenide (InGaAs). These are orders of magnitude quieter than typical MIR detectors and often more sensitive. 

Raman spectroscopy may be performed on either a dispersive instrument or a FT instrument. All of the spectra provided in this chapter were obtained from a FT-Raman instrument (see Fig. 62), featuring a NdiYAG solid-state laser, and a InGaAs (indium-gallium arsenide) detector, combined with a silicon on quartz beam splitter. Note that in the FT-Raman experiment, the sample effectively becomes the source to the FT spectrometer. Dispersive Raman instruments are also popular, and these usually feature a silicon-based array detector (CCD array) in combination with either a visible laser (doubled YAG or HeNe) or a short-wavelength solid-state NIR laser. 

Detector. The radiation is detected by infrared-sensitive semiconductors, such as indium gallium arsenide (InGaAs) or mercury cadmium telluride (HgCdTe, but often abbreviated MCT). Infrared light striking these materials can promote electrons into conduction, allowing the radiation to be detected as an electrical current. 

JR Gilchrist, J Rebbello, D Lanzisera, J Noonan. Indium gallium arsenide detectors open up the near-IR. Laser Focus World 149-156, May 2000. 

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