Theoretical/Numerical Studies of the Nanoscale-cavity Effects on Dipole Emission, Förster Resonance Energy Transfer and Surface Plasmon Coupling

The electric field and radiated power of a radiating dipole located inside a spherical nano-cavity are formulated to show that the nano-cavity structure or nanoscale-cavity effect can enhance the near-field intensity inside the cavity and the far-field radiated power of the dipole. Such enhancements are caused by two contributing factors, including the classical electromagnetic scattering as formulated and the Purcell effect, which is implemented through a numerical feedback process by assuming a two-level system for the radiating dipole. The enhancement of near-field intensity results in the efficiency increase of Förster resonance energy transfer when both energy donor and acceptor are located inside the nano-cavity. By combining the enhancements of the field intensity of the donor and the radiated power of the acceptor, the color conversion efficiency can be increased through the nanoscale-cavity effect. We also numerically demonstrate that the nanoscale-cavity effect can enhance surface plasmon coupling for increasing the radiated power of a dipole located nearby an Ag nanoparticle inside a nano-cavity.