Scientists have created an ultra-fast light-emitting device that sets a new speed record.
The incredible innovation has the ability to flip on and off 90 billion times a second, a breakthrough that could lead to efficient optical computing, Duke University reported.
Smartphone batteries already power billions of transistors to switch on and off several times per second with electrons, but using photons instead could help computers function even faster. In order to accomplish this, researchers must create a light source that can turn on and off at breakneck speeds. Duke researchers have now gotten step closer to realizing this desired light source by pushing a semiconductor quantum dots to emit light at more than 90 gigahertz.
"This is something that the scientific community has wanted to do for a long time," said Maiken Mikkelsen, an assistant professor of electrical and computer engineering and physics at Duke. "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 speed is achieved through a system of plasmonics in which a laser shines onto a silver cube, causing free electrons on its surface to oscillate in a wave. The oscillations collect light, which in turn react with the free electrons. Plasmon (energy trapped on the surface of the nanocube) creates an intense electromagnetic field between the silver nanocube and a thin sheet of gold. The subsequent field interacts with quantum dots, causing them to produce a directional, efficient emission of photons that can be turned on and off at more than 90 gigahertz.
"There is great interest in replacing lasers with LEDs for short-distance optical communication, but these ideas have always been limited by the slow emission rate of fluorescent materials, lack of efficiency and inability to direct the photons," said Gleb Akselrod, a postdoctoral research in Mikkelsen's laboratory. "Now we have made an important step towards solving these problems."
Now, the researchers plan to use the plasmonic structure to create a single photon source as well as figure out the best placement for quantum dots to create the fastest fluorescence rates.
"By tailoring the environment around a material, like we've done here with semiconductors, we can create new designer materials with almost any optical properties we desire," Mikkelsen said. "And that's an emerging area that's fascinating to think about."
The findings were published in a recent edition of the journal Nature Communications.
