Plasmon-emitter interaction using integrated ring grating-nanoantenna structures

TL;DR

This paper introduces integrated ring grating-nanoantenna structures that enhance nanoscale optical focusing and fluorescence emission through plasmon-emitter coupling, combining the advantages of SPPs and LSPs for improved nanophotonic applications.

Contribution

The work presents novel integrated plasmonic structures that enable controlled SPP-LSP coupling, improving optical resolution and emitter fluorescence beyond traditional limits.

Findings

Enhanced fluorescence emission observed in experiments

FDTD simulations confirm strong plasmon-emitter coupling

Comparison shows structure-specific effects on photoluminescence

Abstract

Overcoming the diffraction limit to achieve high optical resolution is one of the main challenges in the fields of plasmonics, nanooptics and nanophotonics. In this work, we introduce novel plasmonic structures consisting of nanoantennas (nanoprisms, single bowtie nanoantennas and double bowtie nanoantennas) integrated in the center of ring diffraction gratings. Propagating surface plasmon polaritons (SPPs) are generated by the ring grating and coupled with localized surface plasmons (LSPs) at the nanoantennas exciting emitters placed in their gap. SPPs are widely used for optical waveguiding but provide low resolution due to their weak spatial confinement. Oppositely, LSPs provide excellent sub-wavelength confinement but induce large losses. The phenomenon of SPP-LSP coupling witnessed in our structures allows achieving more precise focusing at the nanoscale, causing an increase in the fluorescence emission of the emitters. FDTD simulations as well as experimental fabrication and optical characterization results are presented to study plasmon-emitter coupling between an ensemble of dye molecules and our integrated plasmonic structures. A comparison is given to highlight the importance of each structure on the photoluminescence and radiative decay enhancement of the molecules.