Coherent Excitation and Control of Plasmons on Gold Using Two-Dimensional Transition Metal Dichalcogenides

Jan Vogelsang, Lukas Wittenbecher, Deng Pan, Jiawei Sun, Sara Mikaelsson, Cord L. Arnold, Anne Lhuillier, Hongxing Xu, Anders Mikkelsen

Research output: Contribution to journalArticlepeer-review

1 Citation (SciVal)

Abstract

The hybrid combination of two-dimensional (2D) transition metal dichalcogenides (TMDs) and plasmonic materials open up novel means of (ultrafast) optoelectronic applications and manipulation of nanoscale light-matter interaction. However, control of the plasmonic excitations by TMDs themselves has not been investigated. Here, we show that the ultrathin 2D WSe2 crystallites permit nanoscale spatially controlled coherent excitation of surface plasmon polaritons (SPPs) on smooth Au films. The resulting complex plasmonic interference patterns are recorded with nanoscale resolution in a photoemission electron microscope. Modeling shows good agreement with experiments and further indicates how SPPs can be tailored with high spatiotemporal precision using the shape of the 2D TMDs with thicknesses down to single molecular layers. We demonstrate the use of WSe2 nanocrystals as 2D optical elements for exploring the ultrafast dynamics of SPPs. Using few-femtosecond laser pulse pairs we excite an SPP at the boundary of a WSe2 crystal and then have a WSe2 monolayer wedge act as a delay line inducing a spatially varying phase difference down to the attosecond time range. The observed effects are a natural yet unexplored consequence of high dielectric functional values of TMDs in the visible range that should be considered when designing metal-TMD hybrid devices. As the 2D TMD crystals are stable in air, can be defect free, can be synthesized in many shapes, and are reliably positioned on metal surfaces, using them to excite and steer SPPs adds an interesting alternative in designing hybrid structures for plasmonic control.

Original languageEnglish
Pages (from-to)1607-1615
Number of pages9
JournalACS Photonics
Volume8
Issue number6
DOIs
Publication statusPublished - 2021 Jun

Subject classification (UKÄ)

  • Physical Sciences

Keywords

  • metal semiconductor hybrid systems
  • surface plasmon polaritons
  • time-resolved photoemission electron microscopy
  • transition metal dichalcogenides
  • ultrafast plasmonics

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