Multiphoton Photoemission Microscopy of High-Order Plasmonic Resonances at the Ag/Vacuum and Ag/Si Interfaces of Epitaxial Silver Nanowires

• DOI: 10.1021/acsphotonics.6b00353
• Publication Date: 2016-07-08T13:41:42Z
• Authors: Maciej Da̧browski; Yanan Dai; Adam Argondizzo; Qiang Zou; Xuefeng Cui; Hrvoje Petek
• Keywords: Nanophotonics; Photoemission electron microscopy

Understanding the physics of surface plasmons and related phenomena requires knowledge spatial, temporal, spectral distributions total electromagnetic field excited within nanostructures their interfaces, which reflects mode excitation, confinement, propagation, damping. We present a microscopic spectroscopic study plasmonic response in single-crystalline Ag wires grown situ on Si(001) substrates. Excitation modes with broadly tunable (UV–IR) femtosecond laser pulses excites ultrafast multiphoton photoemission, whose spatial distribution is imaged an aberration-corrected photoemission electron microscope, thereby providing time-integrated map locally enhanced fields. show by tuning wavelength, polarization, k-vector incident light that for few micrometers long we can selectively excite either propagating plasmon polariton or high-order multipolar resonances Ag/vacuum Ag/Si interfaces. Moreover, upon excitation wavelength from UV to near-IR regions, find resonant shift top selvedge at interface. Our results, supported numerical simulations, provide better understanding optical metal/semiconductor structures guidance toward design polaritonic nanophotonic devices properties, as well suggest mechanisms plasmonically photocatalysis.