Terahertz radiation quantum dot detectors
Terahertz photons could resonantly excite plasma oscillations in quantum dot (QD) formed in two dimensional electron gas (2DEG). The plasma oscillations in decay by emitting the electrons from the QD, thus leaving the QD in a charge excited state. The latter is probed by a sensitive electrometer placed nearby, such as a single electron transistor (SET) or a point contact (PC), see the picture. In such a way a single photon detector of terahertz radiation can be made. There are interesting phenomena behind operation of these QD-SET and QD-PC sensors, including physics of plasma oscillations, Coulomb blockade, quantum wells, and cryogenic temperatures. As well it is a challenging task to fabricate such a nano-scale device. There is even more interesting and challenging task of application of the single photon THz sensors: deep space observation, health screening, security surveillance. In our group we cover all these areas, which makes research stimulating, exciting and rewarding.