Broadband tunable terahertz absorber based on vanadium dioxide metamaterials

TLDR

An active absorption device is proposed based on vanadium dioxide metamaterials. By controlling the conductivity of vanadium dioxide, resonant absorbers are designed to operate across a broad terahertz frequency range. Numerical simulations demonstrate a broadband terahertz absorber achieving nearly 100 % absorptance with a 60 % bandwidth at 90 % absorptance under normal incidence for both polarizations when the vanadium dioxide conductivity is 2000 Ω⁻¹ cm⁻¹, and that absorptance can be tuned continuously from 30 % to 100 % by varying conductivity from 10 to 2000 Ω⁻¹ cm⁻¹, with spectra independent of polarization and incident angle, indicating suitability for tunable spectral applications such as sensors, detectors, and thermophotovoltaic devices.

Abstract

An active absorption device is proposed based on vanadium dioxide metamaterials. By controlling the conductivity of vanadium dioxide, resonant absorbers are designed to work at wide range of terahertz frequencies. Numerical results show that a broadband terahertz absorber with nearly 100% absorptance can be achieved, and its normalized bandwidth of 90% absorptance is 60% under normal incidence for both transverse-electric and transverse-magnetic polarizations when the conductivity of vanadium dioxide is equal to 2000 Ω-1cm-1. Absorptance at peak frequencies can be continuously tuned from 30% to 100% by changing the conductivity from 10 Ω-1cm-1 to 2000 Ω-1cm-1. Absorptance spectra analysis shows a clear independence of polarization and incident angle. The presented results may have tunable spectral applications in sensor, detector, and thermophotovoltaic device working at terahertz frequency bands.