Electrically Controlled Terahertz Intensity Modulators Based on Dual Fabry–Pérot Cavity Resonant Coupling

Abstract Electronically controlled modulation devices with highly tunable intensities operating in the terahertz (THz) band must be developed and improved for the integration and miniaturization of THz‐based systems. Notably, electronic THz modulation devices suffer from a trade‐off between low insertion loss and high modulation depth, which cannot be simultaneously achieved. In this work, a THz intensity modulation mechanism based on dual Fabry–Pérot cavity resonant coupling is proposed, modeled, and described. The electrically tunable intensity modulator is composed of quartz/PEDOT:PSS:DMSO/EMIM‐TFSI/gold/quartz. The reflectivity of the PEDOT:PSS:DMSO layer can be tuned using an electrical gate, thus adjusting the coupling between the two cavities. In this way, near‐perfect intensity modulation (modulation depth of 94.5%) is achieved at 0.64 THz. A controllable THz amplitude grating, which can switch between three modes through electronic control, is also designed to modulate the angle distribution of the reflected wave. Additionally, a 3 × 5 intensity modulation array with individually controlled pixels is built, and 10 Arabic numerals are displayed to demonstrate the validity of the device. This research not only supports the development of innovative THz modulators but also provides an opportunity for exploring the topological dynamics of multicavity resonance.