Tiny terahertz laser could be used for imaging, chemical detection

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Terahertz radiation — the band of the electromagnetic spectrum between microwaves and visible light — has promising applications in medical and industrial imaging and chemical detection, among other uses.

But many of those applications depend on small, power-efficient sources of terahertz rays, and the standard method for producing them involves a bulky, power-hungry, tabletop device.

For more than 20 years, Qing Hu, a distinguished professor of electrical engineering and computer science at MIT, and his group have been working on sources of terahertz radiation that can be etched onto microchips. In the latest issue of Nature Photonics, members of Hu’s group and colleagues at Sandia National Laboratories and the University of Toronto describe a novel design that boosts the power output of chip-mounted terahertz lasers by 80 percent.

Terahertz radiation — the band of the electromagnetic spectrum between microwaves and visible light — has promising applications in medical and industrial imaging and chemical detection, among other uses.

But many of those applications depend on small, power-efficient sources of terahertz rays, and the standard method for producing them involves a bulky, power-hungry, tabletop device.

For more than 20 years, Qing Hu, a distinguished professor of electrical engineering and computer science at MIT, and his group have been working on sources of terahertz radiation that can be etched onto microchips. In the latest issue of Nature Photonics, members of Hu’s group and colleagues at Sandia National Laboratories and the University of Toronto describe a novel design that boosts the power output of chip-mounted terahertz lasers by 80 percent.

As the best-performing chip-mounted terahertz source yet reported, the researchers’ device has been selected by NASA to provide terahertz emission for its Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) mission. The mission is intended to determine the composition of the interstellar medium, or the matter that fills the space between stars, and it’s using terahertz rays because they’re uniquely well-suited to spectroscopic measurement of oxygen concentrations. Because the mission will deploy instrument-laden balloons to the Earth’s upper atmosphere, the terahertz emitter needs to be lightweight.

Continue reading at Massachusetts Institute of Technology (MIT)

Image: A new technique boosts the power output of tiny, chip-mounted terahertz lasers by 88 percent.

Image Credit: Demin Liu / Molgraphics