Your Cell Phone Will Soon Have X-Ray Vision

A pair of researchers at Caltech have designed a microchip that turns a sensor like a cell phone into a view finder that sees through thin surfaces.

Dec 13 2012, 3:15pm

Do you ever stop to think how much power is locked inside your cell phone? The thin rectangle you carry in your pocket every day is outfitted with a microphone, speaker, plasma display, antenna, battery and an amazingly complex and compact circuit board–all of which is packed into a few cubic inches. 

In a new spin on the same circuit technology, a pair of electrical engineers at the California Institute of Technology has developed a silicon microchip a fraction of the size of a penny that operates at about 300 times the speed and radiates high-frequency electromagnetic waves capable of penetrating hard surfaces. The new chips are, themselves, an antenna–one that is 1,000 times stronger than the one in your phone now. 

Essentially, the engineers devised a way to outfit your phone with a capability that has most of the benefits of x-ray vision–the ability to detect objects through physical barriers–while avoiding the downsides of exposing users to ionizing rays that contribute to cancer. The terahertz waves fall on the electromagnetic spectrum somewhere between infrared radiation and microwaves.

The microchips resting next to a penny. Image: Caltech.

"These chips will enable a new generation of extremely versatile sensors," said Ali Hajimiri, an electrical engineering professor at Caltech who helped develop the new chip.

Hajimiri envisions using the technology to one day non-invasively scan people for cancer and scan cars and trucks at the U.S. border for contraband. He and post-doc Kaushik Sengupta describe their innovation in the December issue of IEEE Journal of Solid-State Circuits. The chips might even pick up the chemical residue of pharmaceutical drugs, cocaine, dynamite and biological weapons. 

A Caltech article introducing the innovation conjures an episode of the TV show 24, describing "a secret agent racing against time" who finds a ticking bomb by scanning "a pile of suspicious boxes in an alleyway" with his cell phone. BOOM: Crisis averted.

The devices that can pull off that kind of detection these days are big and bulky, Hajimiri says, which limits their immediate and practical applications. For now, Hajimiri has used the chips to detect razor blades in plastic containers and teddy bears, and trace the fat content of chicken breast. "The first time we say the actual images, it took our breath away," he said.