Circular Magnetoplasmonic Modes in Gold Nanoparticles

• Published in: Nano letters Vol. 13; no. 10; pp. 4785 - 4789
• Main Authors: Pineider, Francesco, Campo, Giulio, Bonanni, Valentina, de Julián Fernández, César, Mattei, Giovanni, Caneschi, Andrea, Gatteschi, Dante, Sangregorio, Claudio
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.10.2013
• Subjects: Biosensing Techniques; Circular Dichroism; Circularity; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Colloids - chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Gold; Gold - chemistry; Magnetic Fields; Magnetic resonance; Materials science; Metal Nanoparticles - chemistry; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Plasmonics; Plasmons; Refractometry; Slopes; Surface and interface electron states; sensing; magneto optics; Active plasmonics; magnetoplasmonics; gold nanoparticles; Nanoparticles; Gold; Refractive index; Optical properties; Magnetic circular dichroism; Plasmons; Surface plasmon resonance; Nanostructured materials; Implementation
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/nl402394p

The quest for efficient ways of modulating localized surface plasmon resonance is one of the frontiers in current research in plasmonics; the use of a magnetic field as a source of modulation is among the most promising candidates for active plasmonics. Here we report the observation of magnetoplasmonic modes on colloidal gold nanoparticles detected by means of magnetic circular dichroism (MCD) spectroscopy and provide a model that is able to rationalize and reproduce the experiment with unprecedented qualitative and quantitative accuracy. We believe that the steep slope observed at the plasmon resonance in the MCD spectrum can be very efficient in detecting changes in the refractive index of the surrounding medium, and we give a simple proof of principle of its possible implementation for magnetoplasmonic refractometric sensing.