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

We investigated the high Q-factor, high modulation depth, and multiple Fano resonances based on a periodical all-dielectric asymmetric nanocylinder dimer. It is demonstrated that due to excitation of subradiant hybrid modes five sharp Fano resonances can be achieved by breaking symmetry and can be flexibly tuned by geometry. All Fano resonances have a narrow line width, maximal Q-factor exceeds 5000 and even minimal Q-factor also reaches 870. Moreover, modulation depth can reach nearly 100%. In addition, the bulk refractive index sensitivity exceeds 530 nm/RIU, and maximal figure of merit reaches 3350. The proposed array is useful for nonlinear optics and biosensing. (C) 2019 The Japan Society of Applied Physics