- About Us
- Career Center
- Nano-Social Network
- Nano Consulting
- My Account
|A scanning electron microscope image of an organic grating used to excite surface plasmons|
The irradiation of a metal surface with light or electrons can result in the formation of coherent electronic oscillations called surface plasmons, an effect ideal for applications such as optical communications on optoelectronic chips. Unfortunately, however, surface plasmons quickly lose their energy during transit, limiting their on-chip propagation distance. Jing Hua Teng at the A*STAR Institute of Materials Research and Engineering and co-workers from Nankai University and Nanyang Technological University under the Singapore-China Joint Research Program have now developed nanoscale structures that are able to replenish as well as guide surface plasmons on chips. "These structures can be used as plasmonic sources for lab-on-a-chip applications," says Teng.
At the resonance frequency, surface plasmons can generate intense light fields close to the surface, especially in metallic nanostructures. For this reason, surface plasmons have been widely studied for a variety of sensing and light-focusing applications. However, the electrical resistance of metals inevitably causes losses in the movements of the electronic currents involved in surface plasmons. It is therefore important to develop schemes that are able to regenerate surface plasmons as they travel along the surface of a chip.
One possibility is the use of organic light-emitting molecules such as rhodamine B. The researchers embedded molecules of rhodamine B in a polymer matrix that was then poured onto the surface of a silver film. To couple the light emission from rhodamine B to the surface plasmons, the polymer layer was structured into a periodic grating (pictured) matched to the resonance frequency of the plasmons. Adjusting the shape and periodicity of the grating allows the light emitted from the surface plasmons to be tailored.
Similar gratings are also used as mirrors in conventional on-chip semiconductor lasers. This structural similarity raises the possibility of combining the plasmonic effects demonstrated here with existing laser designs—an approach that could well lead to the realization of a plasmonic laser.
The advantage of a plasmonic laser over a semiconductor laser is that it can be made much smaller, which is important for the miniaturization of photonic circuits and on-chip sensing applications. "However, such lasers are difficult to fabricate," says Teng. "A number of challenges remain, including how to sufficiently confine the surface plasmons between the mirrors in this kind of configuration and how to reduce the metal damping losses."
Whether for applications in sensing or the on-chip manipulation of light, the potential of these gratings for replenishing plasmons represents an important step toward making plasmonics the key technology for photonic applications in nanoscience.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering
 Zhang, D. G., Yuan, X. C. & Teng, J. H. Surface plasmon-coupled emission on metallic film coated with dye-doped polymer nanogratings. Applied Physics Letters 97, 231117 (2010).
For more information, please click here
Lee Swee Heng
Copyright © The Agency for Science, Technology and Research (A*STAR)If you have a comment, please Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
|Related News Press|
News and information
Display technology/LEDs/SS Lighting/OLEDs
Graphene-based transparent electrodes for highly efficient flexible OLEDS: A Korean research team developed an ideal electrode structure composed of graphene and layers of titanium dioxide and conducting polymers, resulting in highly flexible and efficient OLEDs June 5th, 2016
Artificial molecules April 3rd, 2016
New microwave imaging approach opens a nanoscale view on processes in liquids: Technique can explore technologically and medically important processes that occur at boundaries between liquids and solids, such as in batteries or along cell membranes March 16th, 2016
Nanoworld 'snow blowers' carve straight channels in semiconductor surfaces: NIST, IBM researchers report important addition to toolkit of 'self-assembly' methods eyed for making useful devices December 28th, 2015
Artificial synapse rivals biological ones in energy consumption June 21st, 2016
Drum beats from a one atom thick graphite membrane June 15th, 2016
Yale researchers’ technology turns wasted heat into power June 27th, 2016
Marrying superconductors, lasers, and Bose-Einstein condensates: Chapman University Institute for Quantum Studies (IQS) member Yutaka Shikano, Ph.D., recently had research published in Scientific Reports June 20th, 2016
A new trick for controlling emission direction in microlasers June 20th, 2016