Measurement of the Ultrafast Temporal Response of a Plasmonic Antenna

TL;DR

This paper measures the ultrafast temporal response of a plasmonic gold nanorod array, revealing potential for sub-20 femtosecond electron switching and applications in ultrafast electron diffraction.

Contribution

It provides the first femtosecond-scale measurement of a plasmonic antenna's temporal response, demonstrating near-field dynamics faster than 20 fs.

Findings

Far-field dispersion less than glass slide

Near-field response faster than 20 fs

Potential for ultrafast electron switching

Abstract

We report a measurement on the temporal response of a plasmonic antenna at the femtosecond time scale. The antenna consists of a square array of nanometer-size gold rods. We find that the far-field dispersion of light reflected from the plasmonic antenna is less than that of a 1.2 mm thick glass slide. Assuming a simple oscillating dipole model this implies that the near-field of the antenna may be used as an electron switch that responds faster than 20 fs. Alternatively, ultrafast electron diffraction may be used to investigate the near-field dynamics of the plasmonic antenna.