Today, IR detectors are widely used for commercial and military applications.
The IR region of electromagnetic radiation spans photon wavelengths of
0.7 mm to ~1 mm. The IR region is generally divided into three subregions:
near IR (NIR) with a range of 700-1400 nm, mid-wavelength IR (MWIR)
with a range of 1400 nm-3 μm, and long-wavelength IR (LWIR) with a range
of 3 μm-1 mm. The origins of IR photons are the gases, liquids, and solids
that make up the universe. These IR sources can both absorb and emit IR
radiation. The dependent relationship of radiation absorption and emission
spectra on wavelength helps us identify and evaluate materials in our universe.
IR detectors make this valuable information observable to humans through
their diverse application in a variety of optical characterization instruments
for planetary exploration, space, astrophysics, and atmosphere radiation
measurement. IR detection and thermal imaging are currently topics of
great interest for both military and commercial applications ranging from
night vision, surveillance, driving aids, fire fighting, and various medical