Active modulation of multiple metamaterial induced transparences in terahertz region

Metamaterial induced transparency (MIT) has great potential in photonic device applications. Here, we design a metastructure with MIT effect generated by destructive interference of bright-dark-dark three modes. Therein, the cross resonator formed by the combination of the cut-wire resonator and the long vertical metal bar (LVMB) act as the bright mode, and two pairs of split ring resonators of different lengths are distributed around the cross resonator as two dark modes, realizing significant multi-band MIT effect. Furthermore, the embedded photosensitive Si island in the broken LVMB can be used to tune the effective length by changing the conductivity, thereby actively controlling the conversion from multi-band behaviors into triple MITs. Our results could achieve the dynamic multi-band switching, which has broad application prospects for optical information processing and communication.