All-plasmonic switching based on thermal nonlinearity in a polymer plasmonic microring resonator.

We experimentally investigated thermal nonlinear effects in a hybrid Au/SiO(2)/SU-8 plasmonic microring resonator for nonlinear switching. Large ohmic loss in the metal layer gave rise to a high rate of light-to-heat conversion in the plasmonic waveguide, causing an intensity-dependent thermo-optic shift in the microring resonance. We obtained 30 times larger resonance shift in the plasmonic microring than in a similar SU-8 dielectric microring. Using an in-plane pump-and-probe configuration, we also demonstrated all-plasmonic nonlinear switching in the plasmonic microring with an on-off switching contrast of 4 dB over 50 mW input power.