Graphene/liquid crystal hybrid tuning terahertz perfect absorber

We present, by simulations, a metastructured graphene/liquid crystal hybrid tuning terahertz perfect absorber that consists of graphene disk resonator arrays above a metallic layer separated with liquid crystal substrate. The liquid crystal refractive index and the graphene Fermi level are utilized to implement double-tuning operation to push the spectra scanning limit of the terahertz absorber. Our simulations demonstrate high performance of a near-linear broad tuning region and near-unity absorbance with wide incident angle and polarization independence. The range of the resonant frequency scan is notably enlarged at a spectral ratio of as high as Δf/f=50% while ensuring absorbance beyond 90%. Such graphene/liquid crystal hybrid tuning scheme would be preferable to push the working-band limit of terahertz perfect absorbers.