The radiative efficiency of plasmonic nanoantennas is often thought to be plagued by non-radiative processes known as quenching. We have used a modal electromagnetic theory based on the concept of quasinormal modes to analyze the mechanisms of spontaneous emission in plasmonic nanoantennas. The theory allows for a quantitative investigation of the interplay between the decay into the antenna mode and the quenching. We provide guidelines to design plasmonic nanoantennas able to overcome quenching. Following these guidelines, we show that surface plasmon generation by inelastic electron tunneling through STM tips can be enhanced by more than two orders of magnitude.
展开▼
