Enhancing device efficiency using a reconfigurable terahertz wavefront modulator based on fermi level of graphene

Abstract

This study investigates a Fermi-level-reconfigurable terahertz wavefront modulator composed of a hybrid material comprising graphene, silver metal, and silicon dioxide. Through theoretical simulation, analysis, and experimental investigations, it is found that graphene plays a crucial role in enhancing the performance of the modulator. Specifically, the presence of graphene increases the limiting factor of the modulator by 0.281, reduces the normalized modal field area by 0.15, decreases the transmission loss, and lowers the gain threshold by 30097 cm−1, thereby improving the efficiency, reliability, and stability of the device. The silicon dioxide and silver metal in the structure act as the primary reflective materials, achieving the effect of a metallic lens and validating the modulator's capability for efficient defocusing. Further investigations reveal that the carrier concentration of graphene can be easily controlled, allowing for manipulation of its physical properties through Fermi-level modulation. When incident light passes through the graphene array, it induces phase variations, altering the transmission path of light and thereby affecting the position of the defocused focal point, enabling dynamic adjustability. Under low Fermi-level control, the modulator achieves a 2πphase adjustment range with an average reflectivity of 75%. Thus, this provides potential for practical applications of more dynamic and tunable microdevices, particularly in the field of laser cutting technology and etching processes.