Perspectives of magneto-plasmonic nanostructures and crystals

May 21, 10:00, CEITEC S (large meeting room)  

Paolo Vavassori  

CIC NanoGUNE, Spain 

Magneto-optical effects are widely used in studying technologically relevant magnetic materials as well as to realize optical devices exploiting non-reciprocal propagation of light. The rapidly developing field of magnetoplasmonics merges the concepts from plasmonics and magneto-optics to realize novel phenomena and functionalities for the manipulation of light at the nanoscale. Owing to the intertwined optical and magneto-optical properties, magnetoplasmonics may also offer a smart toolbox for actively tunable optical ultrathin surfaces and metasurfaces. Here I review fundamentals aspects of the underlying physics and recent advances in this emerging research field. 

A survey of applications to a variety of emerging technologies is presented as an example of the broad scientific and technological perspectives offered by magnetoplasmonics, namely:

- Magnetoplasmonic nanoantennas for ultra-sensitive and label-free molecular detection;

- Ultrathin 2D chiroptical surfaces, built on magneto-plasmonic bimetallic meta-atoms where chiral light transmission is modulated by the externally applied magnetic field;

- 2D magnetoplasmonic crystals, which support collective modes (surface lattice resonances) or surface plasmon polariton modes displaying a two-dimensional photonic band structure that can be engineered to obtain tailored and enhanced magneto-optical response.

- Thermoplasmonics based on bimetallic magneto-plasmonic nanoantennas, for harvesting electromagnetic radiation energy and convert it into heat, which can be used to finely tune the magnetization reversal in networks of interacting nanomagnets.

- Non-concentric magnetoplasmonic-disk/plasmonic-ring-resonator nanocavities supporting multipolar dark modes, where the broken geometrical symmetry of the design enables coupling with free-space light and hybridization of dark multipolar modes of the ring nanoresonator with the dipolar localized plasmon resonance of the magnetoplasmonic disk. Such hybridization results in a multipolar Fano resonance that, when excited, yields an amplification of the magneto-optic response substantially larger than what achievable with bare nanoantennas.