Low‐Power and High‐Contrast Nanoscale All‐Optical Diodes Via Nanocomposite Photonic Crystal Microcavities

Abstract A novel nanoscale integrated all‐optical diode is reported, realized by combining the strong plasmonic responses of gold nanoparticles with the all‐optical tunable properties of polymeric photonic crystal microcavities. Non‐reciprocal transmission properties are achieved based on the effect of surface‐plasmon resonance enhancing the optical non‐linearity and dynamic coupling of asymmetrical microcavity modes. An ultralow‐threshold photon intensity of 2.1 MW cm⁻² and an ultrahigh transmission contrast over 10⁴ are realized simultaneously. Compared with previously reported all‐optical diodes, the operating power is reduced by five orders of magnitude, while the transmission contrast is enlarged by three orders of magnitude.