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The smartphones of the future will feature X-ray cameras

Those X-ray glasses we used to see advertised in the back of comic books may soon become a reality, courtesy of a pair of California Institute of Technology (Caltech) researchers. The difference? This X-ray technology will be built into a smartphone camera, and it might actually work.

Caltech professor Ali Hajimiri and post-doc candidate Kaushik Sengupta have built a working prototype of an X-ray device that can "see" beneath materials like fabrics, cardboards, and skin, and can also sniff out hidden explosives, chemical weapons, and drugs, according to Dell's Tech Page One blog.

The researchers "hacked conventional chip hardware" to fashion their small and relatively cheap CMOS-based device, which uses terahertz waves to penetrate surface materials at a shallow depth and send back "surprisingly detailed images" of what lies underneath, Tech Page One reported.

By positioning a pair of standard CMOS chips "just so and operating them at just the right frequencies," Hajimiri and Sengupta said they were able to generate a high-frequency beam 300 times as powerful as a single chip would be capable of and thus able to tap into the terahertz band of the electromagnetic spectrum, a wavelength range that falls between microwave and infrared.

The Caltech duo's work actually sounds remarkably similar to research being conducted at the University of Texas in Dallas, where a team led by electrical engineering professor Michael O designed a new imaging chip that could turn cell phones into X-ray devices capable of seeing through walls, wood, paper, and other objects.

The UT-Dallas team also used CMOS chips to generate terahertz waves for their X-ray device, which O similarly tipped as a potential addition to common consumer gadgets.

The Caltech researchers said their technology could one day be integrated in a typical mobile device's camera. They envision its applications going well beyond the prurient — for instance, a smartphone or tablet outfitted with an X-ray vision-enabling terahertz receiver could be used by dermatologists to "more accurately and almost instantaneously diagnose melanoma."

The terahertz band would also enable lightning-fast data transfer rates, according to Hajimiri.

"A terahertz signal from a phone could wirelessly transmit hundreds of gigabytes per seconds," Tech Page One quoted the Caltech professor of electrical engineering as saying. However, such a system would require extreme proximity between sender and receiver, on the order of just a few centimeters, Hajimiri said.

What about power efficiency, a big factor in implementing technology in mobile devices using battery power that designers seek to maximize between charges? The researchers say their prototype device "can see into a FedEx box using only 10 milliamps," an application that wouldn't put much of an dent in smartphone or tablet battery.

The Caltech team is still experimenting with the technology, so there are unknowns, like exactly how much power larger tasks would need. But Hajimiri said the prototype can see into a FedEx box using only 10 milliamps, a fraction of what a smartphone's power amplifier creates without breaking a sweat.

"The core concept has been demonstrated. There are no fundamental hurdles to commercialising this technology," Hajimiri told Tech Page One.