▎ 摘　　要

A subwavelength metamaterial consisting of array of aluminium conductors is proposed and numerically analyzed using a finite-element method. This material is suggested for a tunable active band-stop filter working in the farinfrared region. A cell of our metamaterial-based structure is composed of a rhombic- shaped aluminium conductor, a rubidium-bromide dielectric, and a graphene sheet deposited on the dielectric in order to achieve tunability. A strong confinement of electromagnetic energy absorbed in the dielectric results in a highly efficient absorption. The suggested structure with the graphene sheet exposed to air can act as a highly sensitive refractive-index sensor (the sensitivity 6.8 mu m/RIU). Due to a small size of our structure, it reveals perfect absorption at the far-infrared wavelengths and wide-range absorption tuning (from 23.6 to 38.1 mu m). The metamaterials with the above structure can result in perfect absorbers for biomedical sensing.