Extraordinary Fluorescence Enhancement in Metal-Dielectric Core–Shell Nanoparticles

Contrary to a paradigm of metal-enhanced fluorescence, unusually thick dielectric coatings can be very favorable achieve extreme values averaged fluorescence enhancement factor $\bar F\gtrsim 3000$ for emitters located on the surface, or in interior, shell Au@dielectric spherical core-shell particles under realistic conditions, even with 100% intrinsic quantum yield. Thick facilitate high-quality transverse electric (TE) multipole ($\ell=7$) resonances which are shown as major cause reported extraordinary F$.