Coulomb and quenching effects in small nanoparticle-based spasers

Abstract

We study numerically the effect of mode mixing and direct dipole-dipole interactions between gain molecules on spasing in a small composite nanoparticles with a metallic core and a dye-doped dielectric shell. By combining Maxwell-Bloch equations with Green's function formalism, we calculate lasing frequency and threshold population inversion for various gain densities in the shell. We find that gain coupling to nonresonant plasmon modes has a negligible effect on spasing threshold. In contrast, the direct dipole-dipole coupling, by causing random shifts of gain molecules' excitation frequencies, hinders reaching the spasing threshold in small systems. We identify a region of parameter space in which spasing can occur considering these effects.

7 pages, 6 figures

References in corpus (4)

• On-command enhancement of single molecule fluorescence using a gold nanoparticle as an optical nano-antenna
• Fluorescence quenching near small metal nanoparticles
• Electric Spaser in the Extreme Quantum Limit
• Spaser as Novel Versatile Biomedical Tool

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