University of Leeds researchers have built the world’s most powerful terahertz laser chip. A paper in the Institution of Engineering and Technology’s (IET) journal Electronics Letters reports that the Leeds team has exceeded a 1W output power from a quantum cascade terahertz laser.
The new record more than doubles landmarks set by a team from Vienna last year, according to the group.
Widely publicised potential applications of terahertz waves include monitoring pharmaceutical products, remote sensing of chemical signatures of explosives in unopened envelopes, and the non-invasive detection of cancers in the human body.
However, one of the main challenges for scientists and engineers is making the lasers powerful and compact enough to be useful.
Professor Edmund Linfield, Professor of Terahertz Electronics in the University’s School of Electronic and Electrical Engineering, said: ‘Although it is possible to build large instruments that generate powerful beams of terahertz radiation, these instruments are only useful for a limited set of applications. We need terahertz lasers that not only offer high power but are also portable and low cost.’
The quantum cascade terahertz lasers being developed by Leeds are only a few square millimetres in size.
Professor Linfield said: ‘The process of making these lasers is extraordinarily delicate. Layers of different semiconductors such as gallium arsenide are built up one atomic monolayer at a time. We control the thickness and composition of each individual layer very accurately and build up a semiconductor material of between typically 1,000 and 2,000 layers. The record power of our new laser is due to the expertise that we have developed at Leeds in fabricating these layered semiconductors, together with our ability to engineer these materials subsequently into suitable and powerful laser devices.’
The work was mainly funded by the Engineering and Physical Sciences Research Council (EPSRC).