Magnetoplasmonics deals with the study of systems where the plasmonic and magneto-optical (MO) properties coexist and show a distinct interaction between them. In this kind of systems, the plasmonic properties can become tunable upon application of a magnetic field, or the MO effects can be largely increased by plasmon resonance excitation, as a consequence of the enhancement of the electromagnetic (EM) field in the MO component of the structure. In this last case, the study of the enhanced MO activity in structures with subwavelength dimensions is especially interesting since they may be viewed as nanoantennas in the visible range with MO functionalities. The light harvesting properties of these systems upon plasmon resonance excitation bring as a consequence an enhanced EM field in its interior, and more interestingly in the region where the MO active component is present. Taking advantage of the direct relation between the MO activity and the EM field intensity, we will show first how the MO active component (Co in our case) can be used as a local probe to evaluate the non- uniform distribution of the EM field within a resonant metallic Au/Co/Au nanodisc. Moreover, optimizing the EM field distribution within the structure by maximizing it in the MO components region while simultaneously minimizing it in all the other, non MO active, lossy components, will allow for the development of novel systems with larger MO activity and reduced optical absorption, becoming an alternative to state of the art dielectric MO materials, like garnets. Our approach to face this problem, based on the insertion of a dielectric layer in Au/Co/Au magnetoplasmonic nanodisks, will also be presented. Tthe insertion of this dielectric layer induces an EM field redistribution in such a way to concentrate it in the regions of interest of the nanostructure. These metallo-dielectric systems can exhibit large MO activity and low optical extinction in the high wavelength range.

Póster presentado en la 12th International conference on Near-field Optics, Nanophotonics and Related Techniques (NFO-12), celebrada en San Sebastián del 3 al 7de septiembre de 2012.

Peer Reviewed