Numerical research on terahertz hyperbolic metamaterials composed of interlaced graphene-dielectric multilayers and a microcavity

Hyperbolic metamaterials (HMMs) have attracted wide attention owing to the exotic physical attributes and great application potential. The optical functional devices based on HMM have been the focuses of research. In this work, we propose and numerically analyze a terahertz (THz) HMM device consisting of a graphene-dielectric HMM, aluminum metamaterials composed of square patches, and an interjacent hollow cavity. Both the spectral characteristics and potential applications based on the device are numerically explored and displayed. Due to the impedance matching condition achieved at the top-air interface, the THz device features a single band absorption of 0.95, centered at 0.896 THz. Also, the absorption ability of the device demonstrates a strong robustness to wide incident angles up to 70° for the two orthogonal incident polarizations. In addition, the device is capable of functioning as a THz sensor if the dielectric hollow cavity is replaced by a microfluid cavity design. The sensing capacity of the device is numerically assessed as well, which discloses a maximum refractive index sensitivity of 400 GHz/RIU. Such a novel THz device composed of a graphene HMM offer a feasible option for future multi-functional devices in integrated optics.