Infrapunakiirgus
Infrapunakiirgus, literally “infrared glow” in Finnish, is a term used to describe the emission of infrared radiation by objects at nonzero temperatures, or more broadly the infrared-visible appearance of such radiation when observed with infrared instrumentation. The word combines infrapuna (infrared) and kiirgus (glow or emission). In physics, infrared glow arises from thermal radiation that follows Planck’s law: as temperature increases, an object’s emission shifts toward the infrared and the radiated power grows, producing a measurable glow in the infrared spectrum. In practice, infrapunakiirgus is detected with infrared cameras, bolometers, or spectrometers and is used to assess temperature distributions and heat transfer.
In technology and research, the concept underpins infrared thermography, industrial inspection, and medical thermography, where infrared
The infrared bands are typically categorized into near-infrared (about 0.75–5 μm), mid-infrared (5–25 μm), and far-infrared
See also Infrared radiation, Thermography, Blackbody radiation, Spectroscopy.