Soon, smartphones may have see-through vision

Researchers, including an Indian-origin scientist have developed a new kind of computer chip that could soon allow you to use your smartphone camera to see through walls.

The new kind of computer chip operates in the part of the radio spectrum, known as the terahertz range. In this range, wavelengths of radiation are longer than infrared light and shorter than those of high-frequency radio.

Terahertz radiation can penetrate solids in a way similar to X rays, but because it doesn't carry as much energy, it won't damage tissue, the Discovery News reported.

Such devices have been making their way into law enforcement and security but they are big and expensive to set up.

Now, electrical engineers Ali Hajimiri and Kaushik Sengupta of the California Institute of Technology have managed to bring the size down to something that could fit into a handheld device.

They built a microchip that both broadcasts and receives terahertz radiation.

The chip itself is made with the same technologies used in ordinary cell phones and computers.

The challenge was making one that would transmit and receive terahertz frequencies.

It turned out that having several transistors on the device operating at the same time was the best way to

accomplish that.

The transistors are synchronised in such a way that the waves they generate reinforce certain frequencies and cancel out others.

The researchers still needed to get past another problem: above a certain frequency, a transistor won't work and thus won't amplify a signal. This is called the cut-off frequency.

By operating the transistors in a synchronised way, they were able to get around that problem and make the chip transmit.

A third obstacle was putting an antenna on a silicon chip; silicon tends to absorb radio energy.

By giving both the antenna and the silicon a certain shape, they made something like the resonator on a guitar that broadcasts terahertz frequencies.

One use for it is data transmission -- the higher the frequency of a radio wave, the more information you can cram on it.

Since the signal is a higher frequency than Wi-Fi, it could make for faster downloads.

"You could use it to download pictures from your digital camera in a few seconds," Hajimiri said.

If such a fingernail-sized chip were on a smartphone, it could be used to broadcast terahertz radiation through layers of soft tissue, clothing or the thin walls of a box, the report said.

The reflected signal would be picked up by an adjacent chip and a computer programme would then analyse that information and display an image on the phone's screen.