Photonic Systems Brown Bag Seminar Series

Thursday, April 19, 2007

12 noon , RLE Haus Conf. Room 36-428

"Plasmonics: A tutorial on the fundamentals and applications of a thrilling research field"

Jorge Bravo-Abad

RLE and Physics Department, MIT

Surface plasmons are electromagnetic waves tightly bound to the interface between an insulating dielectric and a metal. The ability of surface plasmons to concentrate and channel light using subwavelength structures, combined with modern nanofabrication techniques, is leading to the development of novel miniaturized photonic devices, which could overcome in the future some of the main limitations of the current electronic technology. The extensive research effort that is being carried out worldwide along these lines is giving rise to a new branch of photonics, usually called plasmonics.

In this tutorial, I will present an introduction to the current research in plasmonics, from both a theoretical and experimental standpoints. In the first part of my talk, I will start by introducing the physics of surface plasmons and showing how their dynamics can be tailored by just structuring the metallic surface where they are propagating. Then I will review the main advances in plasmonics technology: from the first demonstrations of metallic strip waveguides for surface plasmons to the very recent proposal of channel-plasmon-polariton devices.

In the second part of my talk, I will present the basis of a rather surprising effect mediated by surface plasmons: the so-called extraordinary transmission of light through an array of subwavelength holes milled in a metallic film. I will demonstrate that the light transmitted through that system can be several orders of magnitude greater than what is expected from the standard diffraction theory. In this context, I will discuss how finite size effects influence extraordinary transmission properties and the unexpected spatial distribution of light as it emerges from the arrays. Finally, I will show that extraordinary optical transmission phenomena can be found not only in periodic systems but also in quasiperiodic distributions of holes in a metallic screen.