Lensless magneto-optical imaging

Magneto-optical methods, which utilize the interaction of polarized light with the magnetization of the sample in reflection through the magneto-optical Kerr effect or in transmission through the accordant Faraday effect, present prominent and widespread optical microscopy techniques for studying magnetic microstructures. In non-magnetic light microscopy, several alternatives to lens-based imaging have been developed, which offer various advantages, including an improved ratio of field-of-view to magnification. Selected lensless methods also provide access to both intensity and phase information of the probing light field, which presents an additional information channel obtainable from the studied sample. In a proof-of-principle study we verify that the reconstructed magneto-optical intensity obtained from a lensless multiplane recording scheme is in full qualitative agreement with conventional lens-based Faraday microscopy. The additional phase information, not accessible with conventional methods, offers direct access to domain information through the imaginary part of the Faraday or Kerr component in the studied material and allows domain imaging even in a crossed analyzer position or without the use of an analyzer. These findings will open the path to exploit the various established advantages of lensless microscopy for the magneto-optical investigation of magnetic materials.