Broadband tunable terahertz absorber based on vanadium dioxide metamaterials

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 Omega(-1) cm(-1). Absorptance at peak frequencies can be continuously tuned from 30% to 100% by changing the conductivity from 10 Omega(-1)cm(-1) to 2000 Omega(-1)cm(-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. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement