Terahertz semiconductor laser sources have been an active area of research at a handful of leading institutions around the globe over the last decade, including the Universities of Cambridge and Leeds in the UK, and MIT and Harvard in the USA. By developing new laboratory facilities here, as the results to date show, the University of Manchester is the latest addition to this group. This facility enabled him to carry out work aimed at developing, for the first time, photonically mediated wavelength tuning of terahertz quantum cascade lasers grown by his collaborators in the University of Cambridge. This facility is world leading, providing a micro-manipulated cryogenic probe system, which allows one to couple in both microwave and telecom signal into an electronically tunable terahertz quantum cascade laser through waveguides and optical fibres, respectively. This is an extremely flexible system, which will open up a broad range of opportunities for developing terahertz system concepts.
Terahertz photonic devices remain a strong sector worldwide and the field is now moving into applications areas in medicine, security and terabit/sec data communication and the research work from Dr Chakraborty’s group is ideally placed to take advantage of this trend. In particular, the new Terahertz-over-Fibre initiative, a doctoral thesis on which has recently been awarded to one of his PhD students (Md. Khairuzzaman), is adding a new and major strength to the UK effort. For example, this approach complements extremely well plans on UCL’s £6.5M EPSRC joint programme grant with Cambridge and Leeds, where they hope to develop systems for use in fundamental science (e.g. the study of nanostructured and mesoscopic electron systems) and for applications including short-range high-data-rate wireless communications, information processing, materials detection and high resolution imaging in three dimensions.