Far- and Near-Field Broad-Band Magneto-Optical Functionalities Using Magnetoplasmonic Nanorods

We have performed a systematic study of magnetoplasmonic Au/Co/Au nanorods with different long/short axes ratio arranged in a disordered fashion but with the same spatial orientation of their axes. We show that the magneto-optical response can be tuned from the visible to the near-infrared range by changing the long/short axes ratio. Moreover, the analysis of the magnetic field induced polarization conversion indicates a different behavior for the far field and for the near field. In particular, the far field polarization conversion of the nanorod does not depend on the incident polarization, whereas the near field does. This anticipates direct consequences for near-field interactions, since the interacting elements at different spatial positions could give rise to different magneto-optical responses.