Terahertz gap | 0.3 to 30 THz of EM spectrum
The term "Tera" refers to 1012 where as Terahertz refers to region in EM spectrum from 0.1 to 10 terahertz frequencies. THz wavelengths range from 1 mm to 0.1 mm. This terahertz radiation lies between microwave radiation and infrared radiation in the electromagnetic spectrum. It is considered as extension of microwave and mmwave frequency bands. It offers greater communication bandwidth than these frequency bands. It is known by other names such as submillimeter band, T-rays, T-waves, T-lux, T-light etc.
Terahertz frequencies share some properties of both microwave and infrared (IR) radiations. THz waves travel in LOS (Line of Sight) and they are non-ionizing like IR/microwave waves. Moreover similar to microwave, THz frequency waves penetrate wide variety of non-conducting materials such as clothes, wood, paper, plastic, cardboard, ceramics and so on. Terahertz radiation is highly reflected by metals.
What is Terahertz Gap ?
➨At low microwave frequencies, it is easy to produce effective radiation with the help of
oscillating circuits made of high speed transistors.
➨At high frequencies of visible spectrum it is easy to produce radiation effectively with semiconductor lasers.
➨Transistors and other electronic devices have limit at about 300 GHz and practically limited to 50 GHz where as semiconductor lasers have limitation of about 30 THz. There is a region on EM spectrum where these technologies do not meet each other. This is called Terahertz gap.
➨In other words, Terahertz gap is the frequency range from 0.3 to 30 THz of EM spectrum as shown in the figure.
The terahertz frequencies find applications in spectroscopy, pulsed imaging, impulse ranging, communication, sensing, security, mine detection, bio-chemical agent detection and so on. Research in development of viable sources of THz radiations, detectors and modulators have expedited possibilities of use of Terahertz in wireless communications.
Refer advantages and disadvantages of Terahertz frequency waves >>.