Dynamically switchable multifunctional terahertz absorber based on graphene and vanadium dioxide hybrid metamaterials

A multifunctional terahertz absorber based on a hybrid configuration of vanadium dioxide (VO2) and graphene is proposed, which is enabled to dynamically switch between ultrabroadband and double-narrowband absorp-tion characteristics using the phase-shifting property of VO2. When VO2 is in the metallic phase and the Fermi energy level of graphene is 0.01 eV, ultrabroadband absorption from 3.04 THz to 8.78 THz can be achieved. The absorption can be continuously adjusted from 0.7% to 99.9% by changing the conductivity of the VO2 through temperature. When VO2 is in the insulating phase and Fermi energy level of graphene is 0.4 eV, the proposed absorber exhibits a double-narrowband absorption characteristic, achieving 99.8% and 97.3% absorption at 1.79 THz and 4.62 THz, respectively. Since graphene is an electronically controlled material, it is able to dynami-cally modulate the resonant frequency and absorption intensity by changing the Fermi energy level of graphene. In addition, the physical mechanism of the multifunctional absorber is revealed using electric field distribution and the impedance-matching theory. The proposed absorber has potential applications in optical switching, image processing, and stealth technology.(c) 2023 Optica Publishing Group

Automated summary

A multifunctional terahertz absorber based on a hybrid configuration of vanadium dioxide (VO2) and graphene is introduced, capable of switching between ultrabroadband and double-narrowband absorption characteristics using the phase-shifting property of VO2. The absorption can be adjusted by changing the conductivity of VO2 through temperature and the Fermi energy level of graphene. The proposed absorber has potential applications in optical switching, image processing, and stealth technology.