nl0c00196_si_001.pdf (810.13 kB)
Single Molecule Nonlinearity in a Plasmonic Waveguide
journal contribution
posted on 2020-02-24, 20:16 authored by Christian Schörner, Markus LippitzPlasmonic waveguides
offer the unique possibility to confine light
far below the diffraction limit. Past room temperature experiments
focused on efficient generation of single waveguide plasmons by a
quantum emitter. However, only the simultaneous interaction of the
emitter with multiple plasmonic fields would lead to functionality
in a plasmonic circuit. Here, we demonstrate the nonlinear optical
interaction of a single molecule and propagating plasmons. An individual
terrylene diimide (TDI) molecule is placed in the nanogap between
two single-crystalline silver nanowires. A visible wavelength pump
pulse and a red-shifted depletion pulse travel along the waveguide,
leading to stimulated emission depletion (STED) in the observed fluorescence.
The efficiency increases by up to a factor of 50 compared to far-field
excitation. Our study thus demonstrates remote nonlinear four-wave
mixing at a single molecule with propagating plasmons. It paves the
way toward functional quantum plasmonic circuits and improved nonlinear
single-molecule spectroscopy.