Near Field Magneto-Optical Circular Dichroism Using an Apertureless Probe

We present an original magneto-optical Scanning Near-field-Optical Microscope (SNOM) configuration, using an apertureless probe, and devoted to the characterization in transmission of magnetic samples. Our experimental device provides simultaneously the near and far field optical images, in Magneto-optical Circular Dichroism mode (MCD), and the sample surface topography. The preliminary near field images of an iron garnet test-sample reveal surface modifications in the magnetic domain distribution, unresolved in the far field image, and unrelated to the topographic features. The near field image resolution reaches 240 nm, corresponding to the theoretically estimated size of the smallest magnetic structures.