Terahertz Superconducting and Semiconducting Electronics

Practically all parts of the electromagnetic spectrum are used by humankind. However there is a range of frequencies which is still not employed. This is the so-called terahertz (THz) range and the associated problem is called the terahertz gap.

The recent growing interest in terahertz science and technology is due to its many important applications in physics, astronomy, chemistry, biology, and medicine, including THz imaging, spectroscopy, tomography, medical diagnosis, health monitoring, environmental control, as well as chemical and biological identification.

This range of the electromagnetic spectrum is situated between 0.3 and 30 THz, which corresponds to 10–1000 micrometers (wavelength), 1.25–125 meV (energy) or 2.6–290 K (temperature). The THz gap, which is still hardly reachable by either electronic or optical devices, covers temperatures of biological processes and a substantial fraction of the luminosity from the Big Bang.

Terahertz radiation (T-rays) may penetrate human bodies but, in contrast with X-rays, cause no damage. The absorption spectrum of T-rays is frequency- and material-dependent. In a frequency range of a few THz the penetration depth through aqueous solutions is very limited, while plastic materials are practically transparent.

If tuneable and powerful sources and receivers of such radiation are produced everything can be scanned continuously. This would then initiate a new stage in medicine and security. Nanostructure-based THz electronics may have many applications, e.g. in ultra-high bandwidth wireless communication networks, vehicle control, atmospheric pollution monitoring, inter-satellite communication and spectroscopy, to name a few.

The interactions of T-rays with semiconductor superlattices and with vortices in Josephson junctions are under investigation. A series of novel devices such as a room-temperature operating parametric amplifier of T-rays and a Josephson junction-based T-pump generator have been proposed. We also study spontaneous symmetry-breaking, dynamic chaos and ratchet effects in T-driven nanostructures.