UT scientists develop world’s smallest laser

Alex Raisch

UT physics researchers have created the world’s smallest nanolaser that could lead to faster and more efficient circuits.

Collaborating with researchers from China and Taiwan’s National Tsing Hua University, UT physics professors Chih-Kang Shih and Gennady Shvets created the world’s smallest nanolaser, a device capable of producing focused beams of light despite its microscopic size. The laser is so small it cannot be seen by the human eye. Their findings have been published in the latest issue of Science, a worldwide scientific journal. Many believe this technology could pave the way for faster computer chips, other on-chip optical communications and making miniaturized circuits for future research projects.

Shvets said this smaller nanolaser falls into a special category of spasers, which are devices that emit specialized packets of light instead of free photons.

“The key to creating the nanolaser turned out to be the atomically smooth silver film grown in Professor Shih’s laboratory,” Shvets said. “Although a spaser of nano-scale dimensions was theoretically predicted about a decade ago, this is the first time it was realized experimentally.”

The revolutionary fact about the film is not that it’s the first of its kind but that it’s the finest quality to date, Shvets said.

Charlotte Sanders, a physics graduate student working under Shih, said production of a smaller circuit was first conceptualized when researchers were able to produce a smoother and finer silk film.

“Before with lower quality film, the film was so rough when the electron wave moved through the film it quickly dissipated and turned into heat,” Sanders said. “With this very high-quality smooth film the electron can propagate for very long distances.”

Once the significance of the silk film was observed, the researchers were able to alter previously held notions of this technology.

“Before the size of the cavity had to be large compared with the wavelength of light,” Shvets said. “We have now demonstrated that the size of the cavity can be reduced to nano-scale when placed next to smooth metallic film.”

The new laser technology will allow future computer chips to utilize photons the way present chips utilize electrons, Shvets said.

“With this technology you could make an alternative to an electronic circuit and instead of using electricity, you’re using light coupled into electronic oscillations,” Sanders said.