Dual-channel dynamically tunable terahertz broadband perfect absorber based on a VO2 and MoS2 composite structure

Abstract

We innovatively designed a terahertz broadband absorber based on a VO₂ and MoS₂ composite structure. Its core technical advantage lies in the construction of a thermal-electro-optical dual-channel collaborative regulation system. The temperature-sensitive phase transition of VO₂ and carrier concentration n control in MoS₂ together enable precise and flexible modulation in the terahertz band. Under an ambient temperature of 350 K and a MoS₂ carrier concentration of n = 1 × 10¹⁵ cm⁻², the absorber can achieve ultra-broadband perfect absorption in the 2.54–9.86 THz frequency band. When the temperature drops to 300 K and n = 1 × 10¹⁵ cm⁻², the absorption bandwidth and intensity in the low-frequency band decrease significantly, demonstrating the efficient photothermal regulation performance of VO₂. In the high-frequency band, the absorption intensity shows a significant weakening trend with decreasing carrier concentration, confirming the excellent electro-optical modulation capability of MoS₂. This region-specific response characteristics enable independent modulation of different frequency domains. The mechanism of the broadband absorption spectrum was obtained by analyzing the optimal impedance matching and electric field distribution under different conductivities. In addition, the absorber maintains stable performance at incident angles <60° and is insensitive to the polarization state of incident light, laying a reliable foundation for its application in complex scenarios.