The University of Leeds researchers have exceeded 1-W output power from a quantum cascade terahertz laser. The new record more than doubles the 0.47 W set by the Massachusetts Institute of Technology (MIT) and subsequently by a team from Vienna last year.
The THz waves, which lie in the part of the electromagnetic spectrum between infrared and microwaves, can penetrate materials that block visible light and have a wide range of possible uses including chemical analysis, security scanning, medical imaging, and telecommunications. Some widely publicized potential applications include monitoring pharmaceutical products, the remote sensing of chemical signatures of explosives in unopened envelopes, and the non-invasive detection of cancers in the human body.
One of the main challenges for researchers has been making the lasers powerful and compact enough to be useful. Large instruments that generate beams of THz radiation have already been built, but they are only useful for a limited set of applications. Customers need THz lasers that offer high power and are portable and low cost. The researchers at the University of Leeds have met that need by making quantum cascade THz lasers that measure only a few square millimeters.
Terahertz quantum cascade lasers with >1 W output powers
To make the device, layers of different semiconductors such as GaAs are built up one atomic monolayer at a time up to 1,000 or 2,000 layers. The record power of the new laser is due to the fabricating expertise that the researchers have developed, together with the ability to make these materials into suitable laser devices.
The work was mainly funded by the Engineering and Physical Sciences Research Council (EPSRC). Find more information at http://digital-library.theiet.org/content/journals/10.1049/el.2013.4035
Advertisement
