Quantum Emitters Near a Metal Nanoparticle: Strong Coupling and Quenching

We investigate the interplay between quenching and strong coupling in systems that include a collection of quantum emitters interacting with a metal nanoparticle. By using detailed numerical simulations and analytical modeling, we demonstrate that quantum emitters can exhibit strong coupling with the particle dipole resonance at distances at which the quenching to nonradiative channels is expected to dominate the dynamics. These results can be accounted for in terms of the pseudomode character of the higher multipole modes of the nanoparticle and the corresponding reduction of the induced loss rate. These findings expand the current understanding of light-matter interaction in plasmonic systems and could contribute to the development of novel quantum plasmonic platforms.

Figure 1

Schematics of the system under study: a metal nanoparticle is surrounded by a collection of quantum emitters that are homogeneously distributed in a spherical shell and whose dipole orientations are radial.

Figure 2

(a) $J_{\mathrm{NP}}$ in units of ${\mu }^2/(4{\pi }^2{\epsilon }_d{\epsilon }_0\hslash a^3)$ as a function of $\zeta$ and $\omega$. The dashed black line is a guide for the eye that follows the maximum of $J_{\mathrm{NP}}$. (b) Normalized decay rates, ${\gamma }_1$ and ${\gamma }_M$, and quantum yields, $\eta$ and ${\eta }_1$, as a function of $\zeta$ for ${\omega }_0=2.5\mathrm{eV}$.

Figure 3

Contour plots of the light spectra measured at the detector position, which is placed $1\mu \mathrm{m}$ away from the center of the nanoparticle along the $y$ axis. This magnitude is rendered for different values of the number of QEs homogeneously distributed in a shell at $h=1\mathrm{nm}$.

Figure 4

(a) Light spectra at the detector position for ${\omega }_0\approx {\omega }_{\infty }$ and $h=1\mathrm{nm}$. (b) Corresponding polarization spectra for the same cases analyzed in panel (a). (c) Contour plots of the near-field spectrum evaluated at the surface of the metal nanoparticle for $N=10$ and $N=100$. The color scales are identical in both panels [blue (red) corresponds to minimum (maximum) of the $E$ field].

Figure 5

Contour plot: light spectra for ${\omega }_0={\omega }_1$ and $N=100$ as calculated from our numerical formalism. Dashed white lines represent the evolution of the three eigenvalues of Eq. (7) as a function of $\zeta$.