Tailoring directional scattering in double Fano resonances based on coupled resonators metasurface

This work presents an all-dielectric metasurface design consisting of coupled nano-disk and nano-bar resonators. This configuration demonstrates double Fano resonances around the telecommunication wavelengths (1.55 μm). The first resonance originates from the interference of optically induced electric and magnetic modes within the nano-disk, while the second is primarily driven by the nano-bar with a minor influence from the disk. These unique optical properties provide a direct control over the interference of magnetic and electric modes, consequently enabling the engineering of scattering patterns for each nano-resonator. Our simulations reveal that increasing the nano-disk radius enhances the backscattering of both resonances. Additionally, varying the nano-bar width selectively influences the forward scattering of the second resonance while enhancing the backscattering of the first resonance. This tailored directionality holds promise for applications in nano-antennas with unidirectional emission.