Optical bistability based on Bragg grating resonators in metal-insulator-metal plasmonic waveguides

An optically bistable device based on a Bragg grating resonator with a nonlinear medium in metal-insulator-metal waveguides is proposed. Its properties are numerically investigated by a finite-difference time-domain method and further qualitatively analyzed by adopting Airy equation. Cavities with different Q factors are compared with respect to bi-stability. Cavities with a small Q factor lead to a high transmission and a narrow hysteresis loop. The response time of such cavities is found to be in the sub-picosecond region. Our nano-scale switching structure is comparatively easy to fabricate and integrate in plasmonic circuits and promises to be useful for future all-optical computing and communication technology.