MIT Researchers Develop Theory for Powering Chips with Light

A pair of researchers at the Massachusetts Institute of Technology have developed a theory to use light to control and power "smart" microchips capable of adapting to different wavelengths and changing their behavior. If successful in their further research, they expect advances in telecommunications, remote sensing, and a variety of other photonic applications.

Postdocs Peter Rakich and Milos Popovic of MIT's Research Laboratory of Electronics presented their results in the November issue of Nature Photonics. Co-authors were Marin Soljacic, assistant professor of physics; and Erich Ippen, the Elihu Thomson Professor of Electrical Engineering and professor of physics. Work was funded in part by the Army Research Office through MIT's Institute for Soldier Nanotechnologies.

Rakich and Popovic believe they have found a means to use the miniscule energy caused by light bouncing off a surface to power nano-scale motors and machines embedded on a microchip. The devices would be able to self-adapt to the wavelengths of light, and react differently based on input. Current microchips are limited to an "on-off" state and are not capable of adjusting to conditions around them.

Their next step is to build a device to prove their theory has practical application. If successful, the team will have developed one of the first micro-electro-mechanical systems, a microscopic device with 'eyes' and 'ears' and able to function as a self-contained system. Such devices have widespread applications, from medical telemetry to cell phones, and handheld sensors with military and security applications. The United States Army is pursuing a 'smart' uniform for combat soldiers, and looking at being able to remotely monitor soldier's condition as well as location.

By combining light as the means of transmitting information, the limits imposed by wiring would be eliminated, which include problems with heat dispersal caused by the 'friction' created when electrons flow throw a conductor, allowing devices to be constructed on an even smaller scale than currently possible. It also would pave the way for putting sensors in locations difficult, or impossible, for wiring or fiber optics to be placed.

Researchers all over the country have been working on various photonic devices, with the goal of switching from electrical conductivity in microchips to light. A recent development at the University of Illinois created a means for polarizing and limiting light to a single wavelength.

In a press release from MIT, Popovic said "Our objective now is to develop a variety of light-powered micro- and nanomachines with unique capabilities enabled by this technology. But the first step will be to demonstrate the concept in practice.