Highly sensitive triple-band absorption-based RI sensor for blood components detection using multi-ring graphene resonators

This work investigates a tunable metamaterial perfect absorber with a triple-band operating in a terahertz (THz) range capable of detecting blood components. The design consists of a periodically patterned graphene layer with multi-ring resonators on a silica substrate and a gold grounding layer. The designed absorber achieves near-perfect absorption at three narrow resonances: 7.68, 9.15 and 12.16 THz. The four-fold symmetry of the absorber exhibits good tolerance to incident wave angles up to 60 degrees and polarization-insensitive characteristics. Additionally, the absorption peaks exhibit sensitivity to changes in the refractive index of the surrounding medium, achieving a maximum sensitivity of 3.55 THz/RIU. Due to its unique and feasible design with high sensitivity, the proposed design is an excellent sensor for various biomedical applications.