Numerical Investigation of Enhanced and Quenched Radiative Decay Rate for One and Multiple Emitters near a Nanoparticle Surface

In the previous studies, Zhou et al. showed that the enhancement factor of the radiative decay rate of multiple emitters could be significantly smaller than that of one emitter near a silver nanoparticle surface at around its resonance wavelength. An asymmetric line shape was obtained in the enhancement factor spectrum when six or more emitters were included. Using a nanoparticle composed of silver, gold, glass, or materials with artificially defined real (n) and imaginary (k) parts of the index of refraction, we demonstrated that the enhancement factor of the radiative decay rate of six emitters near the nanoparticle surface will be smaller than that of one emitter when the localized surface plasmon resonance is excited. The asymmetric line shape of the enhancement factors for six emitters is affected by both the real and imaginary parts of the indices of refraction of the nanoparticle, and the asymmetric line shape will appear only when the real part (n) of the index of refraction of the nanoparticle is less than that of the environmental medium. The simulations show that a resonance peak in the enhancement spectrum of six emitters will be obtained when the induced electric field inside the particle is antiparallel to the incident polarization direction, whereas a resonance dip appears at wavelengths when the induced electric field inside the nanoparticle is parallel to the incident polarization direction. While the studies explained key parameters affecting the enhancement factor of the radiative decay rate of one and multiple emitters, developing analytical model is still necessary to reveal more physical insight behind the obtained numerical results.

Automated summary

The research found that near the surface of nanoparticles, the enhancement factor of the radiative decay rate of multiple emitters can be significantly smaller than that of one emitter, and has an asymmetric line shape. The real and imaginary parts of the index of refraction of nanoparticles are critical for the enhancement factor of six emitters, and asymmetric line shape appears when the real part is less than that of the environmental medium.