Observation of strong magnetic effects in visible-infrared sum frequency generation from magnetic structures

We have observed very strong magnetization-induced changes of the infrared-visible sum-frequency generation (SFG) intensity from thin magnetic films using a free electron laser as a tunable infrared source. With the help of a magnetic grating a clear resonance is observed due to the excitation of surface plasmon-polaritons. The magnetization dependence of this resonance opens the way for nonlinear magneto-optical SFG studies of magnetic surface excitations.