Infrared (IR)

Electromagnetic radiations of wavelength between the longest visible red (7,000 Angstroms or 7 x 10E4 millimeter) and about 1 millimeter. (See Electromagnetic Radiation.)

The region of the electromagnetic spectrum bounded by the long-wavelength extreme of the visible spectrum (approximately 0.7 m) and the shortest microwaves (approximately 0.1 mm). See electromagnetic spectrum.