An active ultrafast formation and modulation of dual-band plasmon-induced transparency (PIT) effect is theoretically and experimentally studied in a novel metaphotonic device operating in the terahertz regime, for the first time, to the best of our knowledge. Specifically, we designed and fabricated a triatomic metamaterial hybridized with silicon islands following a newly proposed modulating mechanism. In this mechanism, a localized surface plasmon resonance is induced by the broken symmetry of a C2 structure, acting as the quasi-dark mode. Excited by exterior laser pumps, the photo-induced carriers in silicon promote the quasi-dark mode, which shields the near-field coupling between the dark mode and bright mode supported by the triatomic metamaterial, leading to the dynamical modulation of terahertz waves from individual-band into dual-band PIT effects, with a decay constant of 493 ps. Moreover, a remarkable slow light effect occurs in the modulating process, accompanied by the dual-transparent windows. The dynamical switching technique of the dual-band PIT effect introduced in this work highlights the potential usefulness of this metaphotonic device in optical information processing and communication, including multi-frequency filtering, tunable sensors, and optical storage.

磷烯因其层数可调的带隙、高的载流子迁移率及面内各向异性等优点为构建基于二维材料的光电子器件提供了新的选择。用时域有限差分法数值模拟了磷烯π型级联和紧凑结构中的等离激元诱导透明现象，通过改变结构分布及磷烯的费米能级等参数，实现了中红外到远红外的宽范围可调谐等离激元诱导透明。其中，透明窗口数目、强度以及位置均实现了灵活调制。此外，研究了诱导透明窗口对偏振角敏感的特性。所得结果为开发基于磷烯等离激元的生物传感器、光电探测器及光开关等提供了参考。

Recently reported plasmon-induced transparency (PIT) in metamaterials endows the optical structures in classical systems with quantum optical effects. In particular, the nonreconfigurable nature in metamaterials makes multifunctional applications of PIT effects in terahertz communications and optical networks remain a great challenge. Here, we present an ultrafast process-selectable modulation of the PIT effect. By incorporating silicon islands into diatomic metamaterials, the PIT effect is modulated reversely, depending on the vertical and horizontal configurations, with giant modulation depths as high as 129% and 109%. Accompanied by the enormous switching of the transparent window, remarkable slow light effect occurs.

为了降低功耗、实现超快速响应，设计了一种基于双矩形腔边耦合等离子体波导系统，并研究了其等离子体诱导透明效应.采用光学Kerr效应超快调控石墨烯-Ag复合材料波导结构，实现1 ps量级的超快响应时间.动态调控等离子体波导的传输相移，当泵浦光强为5.83 MW/cm²时，等离子体诱导透明系统能够实现透射光谱π相移，这是因为基于石墨烯-Ag复合材料结构等离子体波导具有大的等效光学Kerr非线性系数，表面等离子体激元局域光场和等离子体诱导透明效应慢光对光学Kerr效应产生了协同增强作用，大大降低了系统获得透射光谱π相移的泵浦光强.等离子体诱导透明效应透明窗口的可调谐带宽为40 nm，系统的群延时控制在0.15 ps到0.85 ps之间，并且光波通过间接耦合或者相位耦合机制实现了等离子体诱导透明效应相移倍增效应.耦合模式理论计算结果很好地吻合了时域有限差分法仿真模拟结果，研究结果对于低功耗、超快速非线性响应和紧凑型光子器件的设计和制作具有一定的参考意义.