Photoelectron imaging of modal interference in plasmonic whispering gallery cavities

Pascal Melchior, Deirdre Kilbane, Ernst Jan Vesseur, Albert Polman, Martin Aeschlimann

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

We use three-photon photoemission electron microscopy (PEEM) to investigate the interference of coherently excited dipolar and quadrupolar resonant modes of plasmonic whispering gallery resonators formed by circular grooves patterned into a flat Au surface. Optical scattering and cathodoluminescence spectroscopy are used to characterize the cavity resonance spectra for a wide range of cavity radii and groove depths. Using PEEM, we directly resolve the interference between the modal field distribution of dipolar and quadrupolar modes that are coherently excited at λ = 795 nm under oblique incidence. Characteristic asymmetries in the photoelectron images for both TM and TE excitation are a direct consequence of the coherent excitation of the resonant modes.

Original languageEnglish
Pages (from-to)31619-31626
Number of pages8
JournalOptics Express
Volume23
Issue number25
DOIs
Publication statusPublished - 14 Dec 2015
Externally publishedYes

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