Micro-optical/plasmonic resonator paves the way for power-on-a-chip applications

Aug. 26, 2014
By combining plasmonics and optical microresonators, researchers at the University of Illinois at Urbana-Champaign (Urbana, IL) and Iowa State University (Ames, IA) have created a new optical-amplifier design that operates in the visible (563–675 nm) and can potentially route narrowband optical power on a chip. 

By combining plasmonics and optical microresonators, researchers at the University of Illinois at Urbana-Champaign (Urbana, IL) and Iowa State University (Ames, IA) have created a new optical amplifier design that operates in the visible (563–675 nm) and can potentially route narrowband optical power on a chip.1 A gain medium tethered to a Raman-line-producing whispering-gallery-mode (WGM) resonator, a protein, and a plasmonic surface, the device can amplify one or a few Raman lines produced by the resonator.

The researchers, led by J. Gary Eden, a professor of electrical and computer engineering (ECE) at Illinois and ECE associate professor Logan Liu, found that plasmonic nanostructures can serve as a bridge between photonics and nanoelectronics, to combine the size of nanoelectronics and the speed of dielectric photonics.

At the heart of the amplifier is a microsphere made of polystyrene or glass that is approximately 10 μm in diameter. When activated by an intense beam of light, the WGM resonator formed by the sphere internally generates a narrowband Raman line. Molecules tethered to the surface of the sphere by a protein amplify the Raman signal, and in concert with the nanostructured plasmonic surface in contact to the sphere, the amplifier produces visible (red or green) light having a bandwidth that matches the internally generated signal.

Conventional comparably-sized optical oscillators and amplifiers have typically produced light based on the buildup of a field from the spontaneous-emission background; however, this 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," says Manas Ranjan Gartia, lead author of the article. "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." This characteristic contrasts with previous WGM-based lasers and amplifiers for which the Q is determined solely by the WGM resonator.

Potential medical uses

"Their potential applications in medicine are exciting because the amplifiers are pumped by light that is able to pass through human skin," says Eden. "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."

Source: http://engineering.illinois.edu/news/article/9356

REFERENCE:

1. Manas Ranjan Gartia et al., Scientific Reports (2014); doi: 10.1038/srep06168

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Achromatic Lenses: High-Quality Custom Optics

March 13, 2025
Ensure clarity and accuracy in your optics systems with Lacroix’s achromatic lenses. Explore how our custom solutions minimize chromatic aberration for perfect results.

Manufacturing Considerations for Tolerancing Aspheres

March 13, 2025
Understand the critical factors in manufacturing aspheres and how Lacroix Optics ensures precise tolerancing in every optical component.

Explore Our Videos: Insights into Precision Optics

March 13, 2025
Get an inside look at Lacroix Optics with our collection of informative videos showcasing our capabilities, innovations, and processes.

Optical Assemblies: Reliable and Precise Solutions

March 13, 2025
Ensure your optical system works seamlessly with Lacroix Optics' custom optical assemblies. Discover the precision and reliability we bring to every project.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!