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Proceedings Paper

Observation of pure magnetism at optical frequencies in a plasmonic system (Conference Presentation)

Paper Abstract

In nature, magnetic effects on materials are weaker than their electric counterparts. Magnetic polarizability is especially difficult to achieve at optical frequencies since natural materials are non-magnetic at this frequency range and magnetic effects can thus only be generated by carefully tailoring the spatial distribution of electric permittivity. Plasmonic nanostructures offer a flexible platform to engineer meta-atoms that satisfy such conditions and enhance the local magnetic field. However, thus far, this magnetic enhancement has always been accompanied with an enhancement of the electric response as well, such that pure magnetic modes were not yet observed in plasmonic systems. In this work, we design, fabricate and characterize a novel plasmonic nanostructure, which supports a pure magnetic dipole mode under plane wave excitation without contamination from electric modes. This study employs rigorous multipolar mode analysis and clearly distinguishes magnetic dipole and electric quadrupole effects. The link between structural asymmetry and multipole composition that is revealed in this work will be particularly useful in research on symmetry-sensitive physical phenomena, including optically induced atomic transition, optical forces, fluorescence, thermal emission and nonlinear optics.

Paper Details

Date Published: 17 September 2018
Proc. SPIE 10722, Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVI, 107220Q (17 September 2018); doi: 10.1117/12.2321160
Show Author Affiliations
Olivier J. F. Martin, Ecole Polytechnique Fédérale de Lausanne (Switzerland)

Published in SPIE Proceedings Vol. 10722:
Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVI
Din Ping Tsai; Takuo Tanaka, Editor(s)

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