Graphene based highly sensitive refractive index sensor using double split ring resonator metasurface

A micrometer highly sensitive refractive index sensor comprising of double split ring metallic resonator placed above graphene layer is proposed. The sensitivity of the refractive index sensor is measured for hemoglobin biomolecule concentrations. The sensitivity of 5000 nm/RIU (Refractive Index Unit) over hemoglobin biomolecule with a different refractive index ranging from 1.34 to 1.43 are analyzed. A numerical investigation is performed between wavelength range from 55 µm to 95 µm to measure the sensing performance of the sensor. The absorption response is analyzed for change in thickness of double split-ring resonator metasurface, substrate thickness, and ground plane thickness In addition that absorption response is also observed with the change in chemical potential (µ_c) of graphene and with different angles of incidence. The absorption response in the structure in term of the electric field with four different wavelengths are also presented. The comparative analysis with previously published structures is also presented in this paper. The proposed refractive index sensor structure is used to sense the hemoglobin biomolecules have better performance in terms of sensitivity compared to all the other designs. Due to its simple structure and easy fabrication steps, the refractive index sensor could be a potential device to be used in medical and diagnostic applications.