Plasmon Laser Demonstrates Fastest Switching Speed

A new plasmon semiconductor laser has demonstrated ultrafast switching speeds and is being touted as the world’s fastest.

The laser was created at Imperial College London and Friedrich Schiller University Jena using semiconductor nanowires with a surface made of zinc oxide, rather than a conventional glass surface. This new ultrafast laser is the fastest to date, the researchers said, with the ability to turn on and off at one thousand billion times per second — a thousand times faster than existing lasers.

Researchers demonstrate ultrafast laser response time. Courtesy of Imperial College London.

In 2012, scientists at the University of Central Florida were able to generate an ultrafast laser pulse of 67 as. Until now, that was the world’s fastest.

In this most recent study, the researchers shrank the nanowire laser via surface plasmons, which allowed the light to be squeezed into a smaller space inside the laser, prompting light to interact more strongly with the zinc oxide. The stronger interaction accelerated the rate at which the laser could be turned on and off to 10 times that of a conventional nanowire laser that uses a glass surface.

“This work is so exciting because we are engineering the interaction of light and matter to drive light generation in materials much faster than it occurs naturally,” said Dr. Rupert Oulton, a physics researcher at Imperial College. “When we first started working on this, I would have been happy to speed up switching speeds to a picosecond, which is one trillionth of a second. But we’ve managed to go even faster, to the point where the properties of the material itself set a speed limit.”

Lasers that can switch on and off at ultrafast speeds are especially important for data communication. Such speeds “means more information carrying 1s and 0s per second, allowing much faster data communications,” said Imperial College doctoral candidate Themis Sidiropoulos.

The work was funded by the Engineering and Physical Sciences Research Council (EPSRC) and the Deutsche Forschungsgemeinschaft. The research was published in Nature Physics (doi: 10.1038/nphys3103).

For more information, visit www3.imperial.ac.uk.