Linear and nonlinear Fano resonance on two-dimensional magnetic metamaterials

We demonstrate that both linear and nonlinear Fano resonances can be realized on two dimensional magnetic metamaterials. The Fano resonance comes from the interference between localized magnetic plasmon resonance and propagating surface plasmon polaritons. When studying the linear optical response of the metamaterial structure, this interference phenomenon was observed in the ellipsometric spectrum. By finely tailoring the geometrical parameters of the magnetic metamaterial device, the nonlinear Fano response was tuned to a near-infrared wavelength (1.61-1.8 μm) of femtosecond pump laser, and Fano-type modulation of the third harmonic generation was found and agrees well with our theoretical model.