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Plasmonic Surfaces

An overview of the group's research into plasmonics.

The field of plasmonics aims to exploit the unique optical properties of nanometallic structures to control and manipulate light at the nanoscale. The optical response of these structures is unique because, unlike dielectrics, metals (such as gold and silver) have a negative dielectric function, which allows them to support collective electron excitations known as ‘surface plasmons’. These resonances exist between the metal surface and the surrounding dielectric and produce extremely high local electric field intensities. Moreover, these properties are not present in the constituent bulk material.

Plasmonically-enhanced Solar Cells

plasmonically-enhanced solar cells
Using nanostructures which support strong localised plasmons, we are able to enhance the efficiency of ultrathin low cost solar cells by up to four times. This strategy can provide new routes to mass market photovoltaics.

 

Plasmonic Rolls of Plasmene

plasmonic rolls of plasmene
Just a single layer of graphene can be rolled up to into carbon nanotubes, we have created plasmene sheets which can be rolled up to create plasmonic tubes. The colours of these tubes change with their morphology, and they can be rolled and unrolled by shining on light.

 

Plasmonic Sensing by Raman

plasmonic sensing by Raman
Because the optical fields produced by plasmons are so strong, molecules in these fields can be detected extemely sensitively. The weak changes in colour of a scattered laser give the vibrational fingerprints of molecules. This allows to watch chemistry and nanoparticles on surfaces in exquisite detail.

 

Surface-enahanced CARS

surface-enahanced CARS
The strong optical fields in plasmons also allow the enhancement of a traditional molecular sensing technique called CARS, which uses multi-colour pulsed lasers. We demonstrate a new technique which million-fold enhancements allowing direct imaging, for instance of biosamples.

 

References

[5] “Surface-Enhanced Coherent AntiStokes Raman Scattering on Nanostructured Au Surfaces”, Nano Lett 11, 5339 (2011)

[4] “From microns to kissing contact: dynamic positioning of two nanosystems”, App.Phys.Lett. 99, 053110 (2011)

[3] “Precise sub-nm plasmonic junctions within Au nanoparticle assemblies using CB glue”, ACS Nano 5, 3878 (2011)

[2] “Enhancing Solar Cells with Localised Plasmons in NanoVoids”, Opt. Exp. 19, 11256 (2011)

[1] “Dressing Plasmons in Particle-in-Cavity Architectures”, Nano Letters 11, 1221 (2011)