Terahertz Wave Reflection Regulation Based on Controllable Impedance of Silicon-Based MXene Layers

Efficient regulation of terahertz (THz) waves is crucial for their utilization in THz optical system, communications, imaging, etc. High-efficiency THz wave reflection regulation can be achieved through interface impedance matching. However, there have been no reports of THz wave regulation achieved via silicon-based interface impedance design. In this study, MXene films were fabricated on high-resistance silicon substrates using the self-assembly method, and their resistance were changed by increasing the thickness of the film. The impedance of the Si/ MXene/air interface was continuously adjusted to achieve efficient THz wave attenuation. When approaching the impedance-matched state, the THz reflectivity at the interface is reduced by 83%, while the transmittance decays by approximately 30%. This study also confirmed the variation trend in THz wave reflection intensity resulting from the impedance change of the Si/ MXene/ air interface, employing THz wave tomography imaging technology. The silicon-based functional interface designed in this work, which offers efficient THz wave reflection regulation, presents a novel approach for achieving THz wave transmission regulation.