As the military, science agencies, and communications firms compete for scarce spectrum resources, researchers at Harvard, MIT, and the Army have developed a compact, room temperature, widely tunable terahertz laser that offers the potential for high-bandwidth communications, ultrahigh-resolution imaging, and precise long-range sensing for radio astronomy.
Until now, the terahertz section of the electromagnetic spectrum, which resides between microwaves and infrared and visible light, has been unavailable for most applications because current sources of terahertz frequencies are bulky, inefficient, have limited tuning, or must operate at low temperature.
The new laser, however, is built from commercial, off-the-shelf components and can generate terahertz waves by spinning up the energy of molecules in nitrous oxide, commonly known as laughing gas.
Terahertz waves can be used in wireless communication, carrying information at a higher bandwidth than radar, across distances that scientists can now tune with the new device. The waves might also enable what MIT officials call "T-ray vision" -- the ability to see through clothing, book covers, and other thin materials. Such technology could produce crisp, higher-resolution images than microwaves and be far safer than X-rays.