Call it the “X-ray vision” app: In several years, smartphones could come equipped with a microchip that lets users peer through boxes, walls and other objects. Rather than dangerous X-rays, however, the chip beams out waves in the harmless terahertz frequency, a little-used portion of the electromagnetic spectrum between microwaves and far-infrared.
Terahertz generators historically have been bulky, expensive affairs. But now Caltech researchers have succeeded in crafting terahertz-emitting silicon chips that are smaller than a dime using a standard, inexpensive electronics manufacturing technique. The researchers harnessed an array of tiny transistors operating in unison and designed the whole chip to act essentially as a terahertz antenna. “We took a holistic approach and combined generation and radiation in one place,” says Ali Hajimiri, co-developer of the chip and an electrical engineer at Caltech.
Terahertz waves, sometimes called T-rays, can penetrate fabrics, cardboard and skin but cannot pass as readily through ...
