TY  - JOUR
A1  - Stete, Felix
A1  - Koopman, Wouter-Willem Adriaan
A1  - Bargheer, Matias
T1  - Signatures of strong coupling on nanoparticles
BT  - revealing absorption anticrossing by tuning the dielectric environment
JF  - ACS Photonics
N2  - In the strong coupling regime, exciton and plasmon excitations are hybridized into combined system excitations. The correct identification of the coupling regime in these systems is currently debated, from both experimental and theoretical perspectives. In this article we show that the extinction spectra may show a large peak splitting, although the energy loss encoded in the absorption spectra clearly rules out the strong coupling regime. We investigate the coupling of J-aggregate excitons to the localized surface plasmon polaritons on gold nanospheres and nanorods by fine-tuning the plasmon resonance via layer-by-layer deposition of polyelectrolytes. While both structures show a characteristic anticrossing in extinction and scattering experiments, the careful assessment of the systems’ light absorption reveals that strong coupling of the plasmon to the exciton is not present in the nanosphere system. In a phenomenological model of two classical coupled oscillators, a Fano-like regime causes only the resonance of the light-driven oscillator to split up, while the other one still dissipates energy at its original frequency. Only in the strong-coupling limit do both oscillators split up the frequencies at which they dissipate energy, qualitatively explaining our experimental finding.
KW  - hybrid nanoparticles
KW  - exciton plasmon coupling
KW  - layer-by-layer deposition
KW  - strong coupling
KW  - absorption measurements
Y1  - 2017
U6  - https://doi.org/10.1021/acsphotonics.7b00113
SN  - 2330-4022
VL  - 4
SP  - 1669
EP  - 1676
PB  - American Chemical Society
CY  - Washington
ER  -