Symphony of nanoplasmonic and optical resonators leads to laser-like light emission
Rick Kubetz, Engineering Communications Office
- Professor J. Gary Eden and his team have created microscopic optical systems that are capable of amplifying light and creating ultra-narrowband spectral output.
- The medical application is exciting to the team because it can transmit signals from cells and buried biomedical sensors to electrical and optical networks outside the body.
- The researchers found that plasmonics—metal nanostructures—can serve as a bridge between photonics and nanoelectronics, to combine the size of nanoelectronics and the speed of dielectric photonics.
By combining plasmonics and optical microresonators, ECE ILLINOIS researchers have created a new optical amplifier (or laser) design, paving the way for power-on-a-chip applications.
“Their potential applications in medicine are exciting because the amplifiers are actuated (‘pumped’) by light that is able to pass through human skin. For this reason, these microsphere-based amplifiers are able to transmit signals from cells and buried biomedical sensors to electrical and optical networks outside the body.”
“We have demonstrated a novel optoplasmonic system comprising plasmonic nanoantennas and optical microcavities capable of active nanoscale field modulation, frequency switching, and amplification of signals,” states Manas Ranjan Gartia, lead author of the article, "Injection- Seeded Optoplasmonic Amplifier in the Visible," published in the journal Scientific Reports. “This is an important step forward for monolithically building on-chip light sources inside future chips that can use much less energy while providing superior speed performance of the chips.”
The proposed design is well-suited for routing narrowband optical power on-a-chip. Over the past five decades, optical oscillators and amplifiers have typically been based on the buildup of the field from the spontaneous emission background. Doing so limits the temporal coherence of the output, lengthens the time required for the optical field to grow from the noise, and often is responsible for complex, multiline spectra.
“In our design, we use Raman assisted injection-seeded locking to overcome the above problems. In addition to the spectral control afforded by injection-locking, the effective Q of the amplifier can be specified by the bandwidth of the injected Raman signal,” Gartia said. This characteristic contrasts with previous WGM-based lasers and amplifiers for which the Q is determined solely by the WGM resonator.
In addition to Eden, Liu, and Gartia, co-authors of the paper include Sujin Seo, Junhwan Kim, Te-Wei Chang, Assistant Professor Gaurav Bahl from Department of Mechanical Science and Engineering, and Professor Meng Lu (MSEE '04, PhD '09), who's currently an assistant professor at Iowa State University. The research was done at Micro and Nanotechnology Laboratory at Illinois.