Universal switching of plasmonic signals using optical resonator modes.

We propose and investigate, both experimentally and theoretically, a novel mechanism for switching and modulating plasmonic signals based on a Fano interference process, which arises from the coupling between a narrow-band optical Fabry-Pérot cavity and a surface plasmon polariton (SPP) source. The SPP wave emitted from the cavity is actively modulated in the vicinity of the cavity resonances by altering the cavity Q-factor and/or resonant frequencies. We experimentally demonstrate dynamic SPP modulation both by mechanical control of the cavity length and all-optically by harnessing the ultrafast nonlinearity of the Au mirrors that form the cavity.