Near-field magneto-optical microscopy using surface-plasmon waves and the transverse magneto-optical Kerr effect

摘要

This research investigates the propagation behavior of the optical near field between gold-coated tapered fiber tips and magnetic thin films. From three-dimensional finite-difference time-domain calculations, we verified that p-polarized incident light generated a strong longitudinal electric field in the fiber tip. This longitudinal electric field can propagate in the nanogap with the aid of surface-plasmon waves. The surface-plasmon wave and the transverse magneto-optical Kerr effect were used in near-field microscopy to measure the magnetic images of submicron Ni-Fe dot arrays. Changes of magnetic domains under different external magnetic fields were experimentally verified by near-field magneto-optical microscopy.