Magnetic Fano resonance in silicon concentric nanoring resonator dimers under azimuthally polarized beam excitation

Abstract In this work, we proposed an all-dielectric nanostructure composed of silicon concentric nanoring resonator dimers (Si CNRD). We studied the scattering properties of Si CNRD and demonstrated the magnetic Fano resonance resulting from the interference between a narrow magnetic dipole mode and a broad magnetic dipole mode coupled into Si CNRD excited by an azimuthally polarized beam (APB). The spectral characteristics of the magnetic Fano resonance are characterized quantitatively by a coupled oscillator model. By changing the geometric parameters of the Si CNRD, the wavelength and intensity of the magnetic Fano resonance can be effectively adjusted. The nanostructure we proposed exhibits potential applications in low-loss sensors, nonlinearity, and laser devices.