Ultrafast on-Chip Remotely-Triggered All-Optical Switching Based on Epsilon-Near-Zero Nanocomposites

On-chip-triggered all-optical switching is a key component of ultrahigh-speed and ultrawide-band information processing chips.[1-4] This switching technique, the operating states of which are triggered by a remote control light, paves the way for the realization of cascaded and complicated logic processing circuits and quantum solid chips. Here, a strategy is reported to realize on-chip remotely-triggered, ultralow-power, ultrafast, and nanoscale all-optical switching with high switching efficiency in integrated photonic circuits. It is based on control-light induced dynamic modulation of the coupling properties of two remotely-coupled silicon photonic crystal nanocavities, and extremely large optical nonlinearity enhancement associated with epsilon-near-zero multi-component nanocomposite achieved through dispersion engineering. Compared with previous reports of on-chip direct-triggered all-optical switching, the threshold control intensity, 560 kW/cm2, is reduced by four orders of magnitude, while maintaining ultrafast switching time of 15 ps. This not only provides a strategy to construct photonic materials with ultrafast and large third-order nonlinearity, but also offers an on-chip platform for the fundamental study of nonlinear optics.