Terahertz Applications Group (TAG)
Terahertz radiation has excellent potential to help with the understanding of fundamental and exciting new challenges at the interface between physics, materials chemistry and the life sciences but it is, as yet, largely unexplored. Light located in this range of the electromagnetic spectrum was very difficult to generate until quite recently. Since the 1990s new developments in semiconductor physics and femtosecond laser technology have made it possible to provide light at terahertz frequencies (a frequency of 1 THz equals a wavelength of 0.3 mm) in a relatively simple way.
The terahertz region of the electromagnetic spectrum
Terahertz radiation has unique properties in that it easily penetrates through most polymeric materials and is therefore an exciting new tool to study such materials, which are often opaque at visible frequencies. As well as being a non-destructive probe of materials, in organic molecular crystals terahertz radiation has the important property that it interacts with vibrational modes that extend across large domains of a crystal lattice. This makes terahertz spectroscopy unique: even though it is possible to excite molecules using a variety of energies it is only through the careful selection of the low energy in the terahertz range that it is possible to selectively excite crystal lattice vibrations and study in a unique way the presence and nature of interactions between molecules.
By using terahertz spectroscopy our group is aiming to understand the physical characteristics of a wide variety of materials spanning the fields of pharmaceuticals, catalysis, biologicals, nanotechnology and non-destructive testing.
The terahertz applications group in 2012, from left to right:Samy Yassin, Nick Tan, Ke Su, Axel Zeitler, Juraj Sibik, Denis Ferachou and Hungyen Lin
History of the Group
The terahertz applications group in 2009, from left to right: Lynn Gladden, Ed Parrott, James Collins, Axel Zeitler, Rob May and Roy Li
Research into terahertz spectroscopy and imaging evolved from the activities in the Semiconductor Physics Group at the Cavendish Laboratory in Cambridge. As result of a restructuring of the group Professor Gladden took over some of the research activities in 2004. Since then our group is part of the Department of Chemical Engineering and Biotechnology, though still based at the Cavendish Laboratory. The terahertz applications group and the Magnetic Resonance Research Centre (MRRC) have a very close working relationship and there are a number of areas of mutual research interest in which we are trying to exploit the complementary benefits of both magnetic resonance and terahertz techniques. We continue to work very closely with the Semiconductor Physics Group with regards to device fabrication and quantum cascade laser applications whilst maintaining an independent research programme in terahertz spectroscopy. In addition, we collaborate with a wide range of groups, both academic and industrial, as detailed here.