Plasmonics can Enable all Optical Switching for a Terahertz Bandwidth

http://futuretechnologytrends.com/2011/10/plasmonics-can-enable-optical-switching-for-a-terahertz-bandwidth/
10/28/2011, 10:08 am
Electronic components are shrinking down to extremely small sizes. Currently, cutting-edge processors utilize the 22-nanometer node. This will further scale down over the next decade or so. Silicon has enabled researchers to construct complicated microchips that have billions of units. The doubling pace of fitting miniature devices on a single CPU has slowed somewhat. In the next ten years, the amount of transistors on an integrated circuit probably won’t change as much as in previous decades. Scientists are just not attaining the energy savings, as sizes get smaller (see dark silicon). Photonics is a potential route to overcome a few of these limitations. One main issue with this is the diffraction limit whereby light cannot confine to a location that is much smaller than its wavelength. This makes it difficult to compete with electronics for certain applications. Electrical signals move nearly at the speed of light as well. The benefit of photonics is partially due to the higher frequencies that are considered achievable.

Academics are building optical switches that could allow for a dense integration. There is hope that this may surpass electronic parts in some arenas. They must be greater than the gigahertz performance of electronics to be competitive. To reach this state, a nonlinear switching medium is necessary that has an ultra-fast response. Plasmonics is a way of constraining electromagnetic wave frequencies to a smaller area. A plasmon is a surface oscillation in the density of charge on a conductor-dielectric interface. A quasiparticle called a plasmon polariton couples a photon to a plasmon. These techniques may reduce the size of interconnect links. It could be a method of routing information swiftly on a chip.

Researchers from the University of Southampton along with other collaborators have demonstrated a suitable switching material. This work was published in the journal Advanced Materials. They make the part with a nanostructured gold film. They claim that this device is over one order of magnitude faster than past designs. The speed is in the terahertz range, which is many times what electronics can do. They control light in a 50 nanometer thick region and the light power is only a few milliwatts. Perhaps this can lead to upgraded optical data processing. Integrating electrical and photonic circuitry may become easier to carry out. This might not be a cheap enough. It will possibly be utilized for specific niches where a quicker cycling is crucial. Consumer items would need to have less expensive compounds. There may be many other drawbacks, which prevent this from finding many uses.

The paper is about a nanostructured plasmonic medium for terahertz bandwidth all-optical switching.