FEATURE TERAHERTZ


of excitement I


Cascade


Tom Eddershaw finds that improvements in power of terahertz lasers are making them more attractive as industrial products


n February, a team from the University of Leeds in the UK announced in the journal Electronics Letters that


they had produced more than 1W of terahertz radiation from a quantum cascade laser, more than doubling the previous power output.


The widespread application of terahertz radiation has been impeded by problems in making the lasers powerful and compact enough to be useful, but the


Leeds result offers hope that these obstacles are now gradually being overcome.


Edmund Linfield, professor of terahertz electronics in the university’s School of Electronic and Electrical Engineering, said: ‘The excitement, for us, is threefold. It’s the international aspect for UK-based research, the potential for uptake from industry, and the ability for people to carry out new experiments. This has allowed us to work with


international organisations and partners, which is very exciting. Having 1W power also has the potential to attract industrial players and start to get the concept into a more industrial product. From a basic science point of view, high-powered sources open up regions that were previously unavailable.’ He acknowledged that: ‘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 developed by Leeds are only a few square millimetres in size. Linfield explained that there are two main benefits to increasing the power: a stronger signal-to-noise ratio can be collected and observations can be made from further away. Don Dooley, general manager of Gentec Electro Optics, said: ‘Higher power and higher energy will always attract attention by enhancing performance in certain areas. It could either enhance an existing application or open up new avenues of applications.’ Dooley continued: ‘When we first got involved in this, around seven years ago, most of the customers were from universities


A major practical application of terahertz radiation is in airport security checks. 14 ELECTRO OPTICS l APRIL 2014 @electrooptics | www.electrooptics.com


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