title: Phase-resolved pulse propagation through metallic photonic crystal slabs: plasmonic slow light.
abstract: We characterized the electromagnetic field of ultra-short laser pulses after propagation through metallic photonic crystal structures featuring photonic and plasmonic resonances. The complete pulse information, i.e. the envelope and phase of the electromagnetic field, was measured using the technique of cross-correlation frequency resolved optical gating. In good agreement, measurements and scattering matrix simulations show a dispersive behaviour of the spectral phase at the position of the resonances. Asymmetric Fano-type resonances go along with asymmetric phase characteristics. Furthermore, the spectral phase is used to calculate the dispersion of the sample and possible applications in dispersion compensation are investigated. Group refractive indices of 700 and 70 and group delay dispersion values of 90 000 fs2and 5000 fs2are achieved in transverse electric and transverse magnetic polarization, respectively. The behaviour of extinction and spectral phase can be understood from an intuitive model using the complex transmission amplitude. An associated depiction in the complex plane is a useful approach in this context. This method promises to be valuable also in photonic crystal and filter design, for example, with regards to the symmetrization of the resonances.This article is part of the themed issue 'New horizons for nanophotonics'.
authors.affiliation: Institute of Applied Physics, University of Bonn, Bonn, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Schönhardt
authors.affiliation: Institute of Applied Physics, University of Bonn, Bonn, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Nau
authors.affiliation: Max-Planck Institute for Solid State Research, Stuttgart, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Bauer
authors.affiliation: Max-Planck Institute for Solid State Research, Stuttgart, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Christ
authors.affiliation: 4th Physics Institute, University of Stuttgart, Stuttgart, Germany.
authors.forename: Hedi
authors.initials: H
authors.lastname: Gräbeldinger
authors.affiliation: 4th Physics Institute, University of Stuttgart, Stuttgart, Germany h.giessen@pi4.uni-stuttgart.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Giessen
keywords: Fano resonance; plasmonics; slow light