Events

Sub-wavelength energy localization with plasmonics

Date:	Wednesday 29 November 2006 11:00 - 12:00
Location:	203

Stefan A. Maier
Centre for Photonics and Photonic Materials, Department of Physics, Universityof Bath, Bath, UK

Confining electromagnetic radiation in a controlled manner to volumes far below the diffraction limit holds the promise of closing the existing size gap between electronic and photonic devices. One avenue towards this goal lies in the use of surface plasmon polaritons, coherent electronic excitations at conductive surfaces coupled to the electromagnetic field. By enabling waveguides and cavities with mode sizes below the diffraction limit, plasmonics therefore promises a wealth of applications ranging from biological sensing to nanoscale optical switching using enhanced electromagnetic fields in nanoscale volumes.

This talk will address recent efforts to establish controlled avenues for sub-wavelength energy localization with plasmonics, such as nano-scale cavities and super-focusing structures. While at visible frequencies high electromagnetic confinement is possible due to the intrinsic dielectric response of metals, at lower frequencies the constraints are far more challenging. This is due to the fact that sub-wavelength plasmonic energy confinement occurs in general only at frequencies close to the intrinsic plasma frequency of the conductor. At far-infrared frequencies in the technologically important THz and microwave regimes, another approach is needed.

We will show that the periodic structuring of highly (even perfectly) conducting surfaces allows sub-wavelength energy confinement via the establishment of spoof surface plasmon polaritons, designer electromagnetic surface modes. While structured
planar surfaces enable a new infrastructure for THz technology, corrugated cylindrical and conical structures show a high promise for the guiding and super-focusing of THz radiation.

Bio:

Stefan Maier is a Reader in the Department of Physics at the University of Bath. Before joining the University in fall 2004, he conducted his PhD and post-doctoral studies at the Watson Laboratories of Applied Physics at Caltech in Pasadena, California.