Terahertz frequency band
Terahertz (THz) waves is a part of the electromagnetic spectrum between infrared and microwave radiation corresponding to wavelenghts from 3 mm to 100 µm. In the frequency domain, it consists of the band from 100 GHz to 30 THz (See Fig 1.). For 1 Thz, wavelenght is about 300µm, photo energy is 4.135 meV and period is 1ps. Order of magnitude of THz waves can discovered with this Terahertz frequency converter application.
The main properties of THz are non-ionizing, good penetration in a wide variety of materials (plastic, wood, composite material, clothes, paper, ceramics, etc), except conducting materials (ex: metal and water). Several molecules have spectral fingerprint in the terahertz frequency band.
Due to penetration and spectral properties, terahertz waves can be used for imaging and spectroscopy. They have several applications like non destructive test of material (like composite), astronomy, body scanner, communications, biomedical, etc. Spectral properties are important for molecule identification (explosive, medecine, alcanes or biomedical identification).