▎ 摘　　要

NOVELTY - The utility model claims a tunable refractive index sensor based on metamaterial, the structure comprises three layers; the top layer comprises a gold opening ring resonator, a metal electrode and a graphene opening ring resonator; the middle layer is an aluminium oxide layer acting as a substrate; the third layer is a doped silicon layer; the metal electrodes of the doped silicon layer and the top layer form the positive and negative electrodes to apply the external bias voltage to the graphene open ring resonator. The refractive index sensor of the utility model works in the middle infrared region; it has the advantages of simple structure, easy integration, flexible and tunable. According to different measured objects, technical personnel can change the Fermi level of the graphene by applying an external bias voltage to the graphene open ring resonator, so as to adjust the working wavelength of the refractive index sensor. In addition, since the metamaterial structure has a local electromagnetic field increase, amplifying the evanescent field, the background refractive index sensor has a higher refractive index sensing sensitivity, so that it shows potential application value in the biochemical detection field.