Silicon‐Based Terahertz Meta‐Devices for Electrical Modulation of Fano Resonance and Transmission Amplitude

Abstract Seeking active and effective control over electromagnetic waves has always been an important focus in optics. Fano resonances occur in planar terahertz (THz) metamaterials by introducing a weak asymmetry in a two‐gap split ring resonator. Without extra layers of photoactive materials and microelectromechanical structures, a novel and economical scheme based on silicon‐integrated THz asymmetric metallic split ring metamaterial is proposed to control Fano resonance and transmission amplitude via electrical excitation. The results show that Fano resonance and transmission amplitude abate drastically with the increase of current bias, due to the loading of electrically formed silicon carrier layer. As the current bias is increased, both the thickness and conductivity of silicon carrier layer are modulated simultaneously. The depth range of modulated silicon carrier layer could reach 250 µm. Besides, a THz transmission amplitude modulator with a modulation depth of 93% is also demonstrated. This work significantly expands the function of silicon‐based metamaterials and opens up opportunities for the realization of switchable sensors, filters, and nonlinear devices.