Highly-resolved scanning of magnetic surfaces by FPR integrated on optical fiber

摘要

We present a new type of polymer-based Fabry & ndash;Perot resonator (FPR) for scanning of the magnetic field distribution with submicrometer resolution. FPR structures were fabricated in a single & ndash;step process by three & ndash;dimensional (3D) laser lithography based on the direct writing process in polymer IP & ndash;Dip and integrated at the end of optical fiber. The key optomechanical part is a thin polymer membrane creating the flexible mirror of FPR with a ferromagnetic microsphere sensitive on a vertical component of magnetic field. For the magnetic field distribution analysis, we used a neodymium magnet composed of microcrystalline grains. The measurement was provided by scanning the FPR probe over the magnetic surface of the neodymium magnet. The interaction of the ferromagnetic microsphere with the magnetic field caused changes of the FPR leading to the spectral changes of reflected light. Detection of dip spectral shift allowed very precise lateral resolution of magnetic induction demonstrated on neodymium magnet surface characterization.