High Q-factor multiple Fano resonances for high-sensitivity sensing in all-dielectric metamaterials

Abstract

We design and numerically investigate the high Q-factor, high modulation depth, and multiple Fano resonances based on a periodical all-dielectric asymmetric nanorod dimer in the near-infrared regime. It is demonstrated that, due to the excitation of the subradiant hybrid modes, five sharp Fano resonances can be achieved by breaking the symmetry of the dimer and can be flexibly tuned by varying the geometrical parameters. All five Fano resonances have a narrow line width, the maximal Q-factor exceeds 9700, and even the minimal Q-factor also reaches about 1090 in magnitude. Particularly, the modulation depth can reach nearly 100%. In addition, the maximal figure of merit reaches 5045. Considering the narrow line-width and significant near-field enhancement, five Fano resonances with large modulation depths in the proposed array are useful for lasing, nonlinear optics, and multiwavelength biosensing.