Optical bistability in subwavelength compound metallic grating.

We have investigated the optical bistability behavior based on an electromagnetically induced reflection (EIR) effect in a compound metallic grating consisting of subwavelength slits and Kerr nonlinear nanocavities embedded in a metallic film. The theoretical and simulation results show that a narrow peak in the broad reflection dip possesses a red-shift with increasing the refractive index of coupled nanocavities. Importantly, we have obtained an obvious optical bistability with threshold intensity about ten times lower than that of metallic grating coated by nonlinear material. The results indicate that our structure may find excellent applications for nonlinear plasmonic devices, especially optical switches and modulators.