ACEIZE Tracking the current state of Science and Technology

Researchers at Yale's School of Engineering & Applied Science led by assistant professor Hong Tang have proven that light can be used to push nanoscale switches. Previously it had been proven that the attractive force of light can be used to 'pull' nanoscale switches. Funding for the project was provided by DARPA.

How?
The repulsive force of light is seen when two light beams are out of phase with each other. This is in counter distinction to normal objects. Normally "oppositely charged particles attract each other, but out-of-phase light beams repel each other." This phenomenon only occurs when two beams of light are restricted to wavelength guides. The wavelength guides are different lengths of silicon 'nanowire'. When two light beams are forced to travel the wavelength guides, they become out of phase and will repel each other.

Who Cares?
Microchip manufacturers, I suppose. The linked article mentions that using light to trip switches rather than electrical current will use far less power, and be much faster than conventional chip based switches. Telecommunications was specifically mentioned as an application. I can't help but think of quantum computing being able to benefit from light based switching, too. Faster processing needs faster signals, right?

What's a nanoscale switch?
It's exactly what it sounds like. A nanoscale switch is a very small switch.

In my brief search these switches have primarily been binary switches, meaning they are either off or on. Folks are working with many different materials to construct these switches. In the attached image, a gold wire and a silver wire are laid crosswise to each other, forming plates. In between the two is a self-assembling layer of organic molecules that form on the silver plate. Given certain current, a string of silver will form a connection to the gold plate.

At Ohio University, the chlorophyll-a molecule was modified to behave in a switch like manner. The chlorophyll molecule could be manipulated into four different positions by injecting tunneling electrons into the molecule. The additional electrons 'bent' the phytyl-chain in the chlorophyll. The chlorophyll switch seems a little more mechanical than the gold and silver electrical switch, but it does show the diversity of nanoscale switch research.