Normal-Incidence PEEM Imaging of Propagating Modes in a Plasmonic Nanocircuit.

Research paper by Gary G Razinskas, Deirdre D Kilbane, Pascal P Melchior, Peter P Geisler, Enno E Krauss, Stefan S Mathias, Bert B Hecht, Martin M Aeschlimann

Indexed on: 11 Oct '16Published on: 11 Oct '16Published in: Nano Letters


The design of noble-metal plasmonic devices and nanocircuitry requires a fundamental understanding and control of the interference of plasmonic modes. Here we report the first visualization of the propagation and interference of guided modes in a showcase plasmonic nanocircuit using normal-incidence nonlinear two-photon photoemission electron microscopy (PEEM). We demonstrate that in contrast to the commonly used grazing-incidence illumination scheme, normal-incidence PEEM provides a direct image of the structure's near-field intensity distribution due to the absence of beating patterns and despite the transverse character of the plasmonic modes. Based on a simple heuristic numerical model for the photoemission yield, we are able to model all experimental findings if global plane wave illumination and coupling to multiple input/output ports and the resulting interference effects are accounted for.