Terahertz rays could have a dizzying array of applications, from high-speed wireless networks to detecting cancers and bombs. Now researchers say they may finally have created a portable, high-powered terahertz laser.

Terahertz waves (also called submillimeter radiation or far-infrared light) lie between optical waves and microwaves on the electromagnetic spectrum. Ranging in frequency from 0.1 to 10 terahertz, terahertz rays could find many applications in imaging, such as detecting many explosives and illegal drugs, scanning for cancers, identifying protein structures, non-destructive testing and quality control. They could also be key to future high-speed wireless networks, which will transmit data at terabits (trillions of bits) per second.

However, terahertz rays are largely restricted to laboratory settings due to a lack of powerful and compact terahertz sources. Conventional semiconductor devices can generate terahertz waves ranging either below 1 terahertz or above 10 terahertz in frequency. The range of frequencies in the middle, known as the terahertz gap, might prove especially valuable for imaging, bomb detection, cancer detection and chemical analysis applications, says Qing Hu, an electrical engineer at MIT.