  Linear and nonlinear magneto-photonic properties of periodic arrays of nickel
nanodimers are governed by the interplay of the (local) optical response of
individual nanoparticles and (non-local) diffraction phenomena, with a striking
example of Wood's anomaly. Angular and magnetic-field dependencies of the
second harmonic intensity evidence Wood's anomaly when new diffraction orders
emerge. Near-infrared spectroscopic measurements performed at different optical
wavelengths and grating constants discriminate between the linear and nonlinear
excitation mechanisms of Wood's anomalies. In the nonlinear regime the Wood's
anomaly is characterized by an order-of-magnitude larger effect in intensity
redistribution between the diffracted beams, as compared to the linear case.
The nonlinear Wood's anomaly manifests itself also in the nonlinear magnetic
contrast highlighting the prospects of nonlinear magneto-photonics.

Mesoscale and Nanoscale Physics