Plasmonic refractive index sensing enhanced by anapole modes in metal-dielectric nanostructure array

Abstract Periodic nanostructures consisting of metal-dielectric nanostructures array are studied for refractive index (RI) sensing. The anapole mode of metal-dielectric structure is used to enhance plasmonic resonance and reduce energy losses. High sensitivity RI sensing can be achieved by the nanostructure with circular polarization illumination. Numerical results show that the sensor exhibit almost perfect linearity of resonance wavelength shift with RI ranging from 1.3 to 1.39 with sensitivity of 593 nm RIU −1 . The proposed nanostructure could find applications in biomolecules manipulation and optical sensors.