Molecular coupling of light with plasmonic waveguides

TL;DR

This paper demonstrates how molecules can efficiently couple light into and out of plasmonic waveguides, enabling energy transfer and emission over micrometer distances with potential for nanoscale integration and molecular electronics.

Contribution

It introduces a molecular coupling method for plasmonic waveguides that allows scalable, localized, and versatile light coupling without specialized excitation geometries.

Findings

Energy transfer over ten micrometers mediated by surface plasmons

Observation of surface plasmon coupled emission from donor molecules

Scalable fabrication enabling nanometer precision positioning

Abstract

We use molecules to couple light into and out of microscale plasmonic waveguides. Energy transfer, mediated by surface plasmons, from donor molecules to acceptor molecules over ten micrometer distances is demonstrated. Also surface plasmon coupled emission from the donor molecules is observed at similar distances away from the excitation spot. The lithographic fabrication method we use for positioning the dye molecules allows scaling to nanometer dimensions. The use of molecules as couplers between far-field and near-field light offers the advantages that no special excitation geometry is needed, any light source can be used to excite plasmons and the excitation can be localized below the diffraction limit. Moreover, the use of molecules has the potential for integration with molecular electronics and for the use of molecular self-assembly in fabrication. Our results constitute a proof-of-principle demonstration of a plasmonic waveguide where signal in- and outcoupling is done by molecules.