Devices created to speed up future computers

Led by an Indian-origin physicist, a team of researchers in the US has created novel devices that hold promise to make your computer work as the speed of light, literally.

The devices integrate both optical and electronic signals to perform the most elementary computational operations - processing billions of computational steps to produce even the simplest outputs.

"Imagine if every one of those steps could be made just a tiny bit more efficient with light. It would save precious nanoseconds," explained Swastik Kar, assistant professor of physics at Boston-based Northeastern University.

Since light is extremely fast, the new devices represent a critical breakthrough in making a faster dream computer - in which the processing is done using electrical signals and the signal transfer is done by optics - a reality.

Using graphene, a carbon-based material known for its strength and conductivity, and mechanics of carbon nanotubes, Kar and his colleague Yung Joon Jung discovered that light-induced electrical currents rise much more sharply at the intersection of carbon nanotubes and silicon - compared to the intersection of silicon and a metal as in traditional devices.

"That sharp rise helps us design devices that can be turned on and off using light," Kar said.

This finding has major implications for performing computations, which, in simple terms, also rely on a series of on-off switches.

The first device, called AND-gate, requires both an electronic and an optical input to generate an output. This switch only triggers if both elements are engaged.

The second device, an OR-gate, can generate an output if either of two optical sensors is engaged.

The third device works like the front-end of a camera sensor. It consists of 250,000 miniature devices assembled over a centimetre-by-centimetre surface, said the research published in the journal Nature Photonics.