Using microscopic semiconductor wires positioned atop a silver surface, a team of physicists from Imperial College London and the Friedrich-Schiller-Universität Jena has produced an ultra-fast laser that dramatically accelerates the interaction between light and matter. This world record-breaking laser is exciting because one day, it could help improve data communication by boosting the speed that information can be transferred, among a variety of other potential applications. The work has been published in Nature Physics.
The secret to this new super laser lies in the physicists’ use of silver surfaces, rather than the more traditional glass. Slim layers of metal are ideal because they provide surface plasmons, which are oscillations of excited electrons that propagate along the surface of the material. When the light interacts with these waves, it can be focused more tightly than normal. The plasmons therefore effectively squeeze the light into a much smaller space. In doing so, the interaction between the light and the nanowires, which are composed of zinc oxide, was greatly enhanced.
By boosting this interaction, the team was able to speed up the rate at which the lasers could be switched on and off to ten times faster than that of a conventional nanowire laser that uses glass. Impressively, these lasers are the fastest on record so far. Furthermore, according to study co-author Robert Röder, they may have even achieved the upper limit in terms of speed at which semiconductor lasers such as this can be operated.
But speed is not the only remarkable feature of these new lasers: they are also stable at room temperature. This means that they can be used in a wider variety of applications, for example as a means to improve communication systems by speeding up data transfer. Another possibility is that the light inside the laser could be used in ultra-high resolution imaging systems or biomedical detectors that operate at single-molecule sensitivity.
“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,” senior author Dr. Rupert Oulton from Imperial College London said in a news release. “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.”