Organic Exciton in Strong Coupling with Long-Range Surface Plasmons and Waveguided Modes

Abstract

In this Letter, we demonstrate experimentally the strong interaction between organic semiconductor excitons and long-range surface plasmons. For this purpose, a thin J-aggregated cyanine dye layer is deposited on a thin silver film bounded by two poly(vinyl alcohol) layers. An anticrossing between the long-range surface plasmon and the dye exciton is measured in the dispersion relation and confirmed in luminescence experiments, showing unambiguously the hybridization between the long-range surface plasmon and the dye exciton. The extension of the polaritonic states deduced from the dispersion curves is 50 μm, which represents an increase of more than 1 order of magnitude compared to usual surface plasmon-based polaritons. We believe that the extension of the polariton coherence length can have direct applications to the energy transfer between molecules over long distances in strong coupling, as well as in the modification of the properties of materials (conductivity, second harmonic generation). Strong coupling between an aggregated dye layer and guided modes is also experimentally evidenced in a similar structure. The hybridization between dye exciton and guided modes demonstrated here opens the way to the exploitation of polariton nonlinearities and switching already evidenced in cavities for integrated optics: the strong coupling now occurs directly on the guided mode.

Light Emission by a Thermalized Ensemble of Emitters Coupled to a Resonant Structure

“…This broadening in k‐space corresponds to a narrowing in direct space, namely to a smaller coherence length . This behavior has been reported recently …”

Radiative Pumping and Propagation of Plexcitons in Diffractive Plasmonic Crystals

“…Owing to the coherent coupling of carbon nanotubes across the plasmonic crystal via extended plasmon-photonic modes, the spatial coherence of light emission can be deduced from the dispersion linewidth Δk as L ( k x , k y ) = 2/Δ k x,y . 6 A very good agreement between coherence and propagation lengths for the Y -axis is observed. The smaller values for the array consisting of large nanorods relate to their shorter lifetime (see Supporting Information , Figure S7a).…”

“… 11 , 20 Owing to the ultrasmall mode confinement, even a single plexciton regime under room temperature conditions could be reported. 5 , 13 , 20 In addition to localized modes, more spatially extended and propagating plexcitons 6 , 15 , 21 are considered promising for the coupling of distant emitters 22 and large spatial coherence of light emission. 21 One attractive design involves the collective resonances in one- and two-dimensional periodic metallic structures.…”

Light harvesting enhancement using metal nanoparticles

“…The localized surface plasmon resonance could provide different optical properties in the nanoscale regime such as near field and far field enhancement. The localized surface plasmon resonance optical properties can be tuned by controlling different parameters of metal nanoparticles [18][19][20][21][22][23][24].…”

“…In [23], a description of metal-quantum emitter nanodevices in terms of strong coupling was introduced that is limited to a single coupled mode. In [24], the strong coupling of hybrid nanostructure between semiconductor and metal surface plasmons was investigated without showing the effect of generated harmonics.…”