10 January 2014

COBRA COLLOQUIUM: Friday January 10, 2013 at 15:00 – 16:00 in the Film Theater of Grand Café and Film house De Zwarte Doos

Speaker: Prof. Olivier J.F. Martin

Title: Controlling light at the nanoscale with plasmonic antennas

Abstract: The concept of antenna is extremely well developed at microwave frequencies, where a large variety of geometries with centimetre dimensions are routinely utilized. Over the last decade, progress in nanotechnology has enabled the translation of this concept into the nanoscale, with applications at optical frequencies. While some of these nanostructures are the exact counterpart of microwave antennas, others exploit novel physical phenomena that only exist in the nanoscopic world. In this presentation, I will first briefly review the main properties of optical antennas and their fabrication using different techniques in different coinage metals. I will then describe two different experiments that rely on optical antennas. First, optical trapping at the nanoscale, where nanostructures as small as 10nm can be optically trapped in the near-field of a plasmonic antenna. Second, double-resonant plasmonic antennas that enhance second harmonic generation through optical resonances at the fundamental and second harmonic frequencies. I will then describe more complex plasmonic structures that support Fano resonances and show that the equivalent lumped-circuit theory provides a very good model to describe their response and interpret experiments.

Left to right: Field distribution in a realistic gold dipole antenna; double-resonant optical antenna for second harmonic generation (fundamental and second harmonic field distribution); gold bridge forming a plasmonic break junction; silver heptamer for enhancing second harmonic generation.

Biography: Olivier J.F. Martin is Professor of Nanophotonics and Optical Signal Processing at the Swiss Federal Institute of Technology, Lausanne (EPFL), where he is currently head of the Nanophotonics and Metrology Laboratory and Director of the Doctoral Program in Photonics. His research interests focus on the interactions of electromagnetic fields with low dimension systems, especially in the optical regime. Plasmonics is at the heart of his current research interest, with applications in optical signal processing, plasmonic antennas and biophotonics. Dr. Martin has authored about 200 journal articles and holds a handful of patents and invention disclosures. He has received the 1999 Latsis University prize for contributions to the study of near-field optics and photonic bandgap structures.

Website (including list of publications): www.nanophotonics.ch