Terahertz radiation

Terahertz radiation – also known as submillimeter radiation, terahertz waves, tremendously high frequency (THF), T-rays, T-waves, T-light, T-lux or THz – consists of <a href="/facts/Electromagnetic_wave/Ynx7ujCW">electromagnetic waves</a> within the <a href="/facts/International_Telecommunication_Union/Yn8UKKkw">International Telecommunication Union</a>-designated band of <a href="/facts/Frequency/QUSbPaW8">frequencies</a> from 0.1 to 10 <a href="/facts/Hertz/6Wshj5qm">terahertz</a> (THz), (from 0.3 to 3 <a href="/facts/Hertz/6Wshj5qm">terahertz</a> (THz) in older texts, which is now called "decimillimetric waves"), although the upper boundary is somewhat arbitrary and has been considered by some sources to be 30 THz.
One terahertz is 1012 <a href="/facts/Hertz/6Wshj5qm">Hz</a> or 1,000 GHz. Wavelengths of radiation in the decimillimeter band correspondingly range 1 mm to 0.1 mm = 100 μm and those in the terahertz band 3 mm = 3000 μm to 30 μm. Because terahertz radiation begins at a wavelength of around 1 millimeter and proceeds into shorter wavelengths, it is sometimes known as the submillimeter band, and its radiation as submillimeter waves, especially in <a href="/facts/Submillimeter_astronomy/BAydzm8W">astronomy</a>. This band of electromagnetic radiation lies within the transition region between <a href="/facts/Microwave/HmVSN31Y">microwave</a> and <a href="/facts/Far_infrared/rlup3DSX">far infrared</a>, and can be regarded as either.
Compared to lower radio frequencies, terahertz radiation is strongly <a href="/facts/Absorption_(electromagnetic_radiation)/xBYKt7yS">absorbed</a> by the <a href="/facts/Gas/hVVAoodV">gases</a> of the <a href="/facts/Atmosphere_of_Earth/FV97Am25">atmosphere</a>, and in air most of the energy is <a href="/facts/Attenuation/XP4vX360">attenuated</a> within a few meters, so it is not practical for long distance terrestrial <a href="/facts/Radio/XFr909M2">radio communication</a>. It can penetrate thin layers of materials but is blocked by thicker objects. THz beams transmitted through materials can be used for <a href="/facts/Characterization_(materials_science)/FDzNl7B7">material characterization</a>, layer inspection, relief measurement, and as a lower-energy alternative to <a href="/facts/X-ray/wseP79cN">X-rays</a> for producing high resolution images of the interior of solid objects.
Terahertz radiation occupies a middle ground where the ranges of <a href="/facts/Microwave/HmVSN31Y">microwaves</a> and <a href="/facts/Infrared_light/44XdJNcc">infrared light</a> waves overlap, known as the "<a href="/facts/Terahertz_gap/7UqsFy95">terahertz gap</a>"; it is called a "gap" because the technology for its generation and manipulation is still in its infancy. The generation and <a href="/facts/Modulation/aAXPjINv">modulation</a> of electromagnetic waves in this frequency range ceases to be possible by the conventional electronic devices used to generate radio waves and microwaves, requiring the development of new devices and techniques.

Terahertz radiation open-in-new

Terahertz radiation