  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 {\mu}m) of femtosecond pump laser, and
Fano-type modulation of the third harmonic generation was found and agrees well
with our theoretical model.
