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Short-wavelength infrared SWIR, IR-B DIN: 1.4–3 μm 100–214 THz 413–886 meV 2,070–966 K (1,797–693 °C) Water absorption increases significantly at 1,450 nm. The 1,530 to 1,560 nm range is the dominant spectral region for long-distance telecommunications (see transmission windows). Mid-wavelength infrared MWIR, IR-C DIN; MidIR. [22]
The wavelength range from approximately 200 μm up to a few mm is often referred to as Submillimetre astronomy, reserving far infrared for wavelengths below 200 μm. Mid-infrared , from 30 THz to 120 THz (10–2.5 μm).
The infrared portion of the electromagnetic spectrum is usually divided into three regions; the near-, mid- and far-infrared, named for their relation to the visible spectrum. The higher-energy near-IR, approximately 14,000–4,000 cm −1 (0.7–2.5 μm wavelength) can excite overtone or combination modes of molecular vibrations .
Wavelengths of commercially available lasers. Laser types with distinct laser lines are shown above the wavelength bar, while below are shown lasers that can emit in a wavelength range. The height of the lines and bars gives an indication of the maximal power/pulse energy commercially available, while the color codifies the type of laser ...
As the main part of the 'window' spectrum, a clear electromagnetic spectral transmission 'window' can be seen between 8 and 14 μm. A fragmented part of the 'window' spectrum (one might say a louvred part of the 'window') can also be seen in the visible to mid-wavelength infrared between 0.2 and 5.5 μm.
For the mid-IR region, 2−25 μm (5,000–400 cm −1), the most common source is a silicon carbide (SiC) element heated to about 1,200 K (930 °C; 1,700 °F) . The output is similar to a blackbody. Shorter wavelengths of the near-IR, 1−2.5 μm (10,000–4,000 cm −1), require a higher temperature source, typically a tungsten-halogen lamp.
The terahertz band, from 300 gigahertz to 3 terahertz, can be considered either as microwaves or infrared. It is the highest band categorized as radio waves by the International Telecommunication Union. [4] but spectroscopic scientists consider these frequencies part of the far infrared and mid infrared bands.
Infrared heaters can be operated in vacuum or atmosphere. One classification of infrared heaters is by the wavelength bands of infrared emission. Short wave or near infrared for the range from 750 nm to 1.4 μm; these emitters are also named "bright" because still some visible light is emitted; Medium infrared for the range between 1.4 μm and ...