Researchers Create Light-Emitting Device That Flashes 90 Billion Times Per Second


Researchers have been able to develop a light-emitting device that is able to turn on and off as many as 90 billion times per second. The device could be a way to greatly speed up data transmission in computers.

Things like smartphone batteries currently power transistors by flipping electronics on and off billions of times per second. However, if microchips were able to use photons instead of electrons, computers might be able to operate a lot faster.

To do this, however, engineers first had to create a light source that could be switched on and off extremely fast. While a laser might be able to do this, lasers are too power-hungry.

Researchers at Duke University, however, are getting closer to creating this kind of a light source. A team from the Pratt School of Engineering was able to push semiconductor quantum dots to emit light at over 90 gigahertz.

"This is something that the scientific community has wanted to do for a long time," said Duke assistant professor of electrical computer engineering, Maiken Mikkelsen, in an interview with PhysOrg. "We can now start to think about making fast-switching devices based on this research, so there's a lot of excitement about this demonstration."

The new device was created using a laser that shines on a silver cube, after which the free electrons on the surface of the cube oscillate together in a wave. The oscillations create light themselves, which again reacts with the free electrons on the cube. This energy is called a plasmon.

By placing a sheet of gold only 20 atoms away, an energy field is created between the gold and silver cube. This field then interacts with quantum dots that are sandwiched between the gold and the silver cube, with the quantum dots then producing an emission of photons that can be turned on and off at more than 90 billion times per second.

"The eventual goal is to integrate our technology into a device that can be excited either optically or electrically," said Thang Hoang, another researcher at the laboratory. "That's something that I think everyone, including funding agencies, is pushing pretty hard for."

The team is now working to create one single photon source by only having one quantum dot between the silver cube and the gold sheet. The team is also trying to find the optimum placement and orientation of the quantum dots to create the fastest rate possible.

The research was published in the journal Nature Communications.

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