摘要
Enhancing magneto-optical effects is crucial for reducing the size of key photonic devices based on the non-reciprocal propagation of light and to enable active nanophotonics.Here,we disclose a currently unexplored approach that exploits hybridization with multipolar dark modes in specially designed magnetoplasmonic nanocavities to achieve a large enhancement of the magneto-optically induced modulation of light polarization.The broken geometrical symmetry of the design enables coupling with free-space light and hybridization of the multipolar dark modes of a plasmonic ring nanoresonator with the dipolar localized plasmon resonance of the ferromagnetic disk placed inside the ring.This hybridization results in a low-radiant multipolar Fano resonance that drives a strongly enhanced magneto-optically induced localized plasmon.The large amplification of the magneto-optical response of the nanocavity is the result of the large magneto-optically induced change in light polarization produced by the strongly enhanced radiant magneto-optical dipole,which is achieved by avoiding the simultaneous enhancement of reemitted light with incident polarization by the multipolar Fano resonance.The partial compensation of the magnetooptically induced polarization change caused by the large re-emission of light with the original polarization is a critical limitation of the magnetoplasmonic designs explored thus far and that is overcome by the approach proposed here.
基金
supported by the Spanish Ministry of Economy,Industry and Competitiveness under the Maria de Maeztu Units of Excellence Programme(MDM-2016-0618)
the projects FIS2015-64519-R and RTI2018-094881-B-I00(MINECO/FEDER)
Support from the European Union under the Project H2020 FETOPEN-2016-2017“FEMTOTERABYTE”(Project n.737093)
support from the University of Castilla-La Mancha and the European Regional Development Fund(2018/11744)
support from the Luxembourg National Research Fund(CORE Grant No.13624497 ULTRON)
the FEDER program(grant n.2017-03-022-19 Lux-Ultra-Fast).
