SCANNING NEAR-FIELD OPTICAL MICROSCOPE FOR THE IMAGING OF MAGNETIC DOMAINS IN OPTICALLY OPAQUE MATERIALS

We describe a scanning near-field optical microscope capable of magnet ic imaging in optically opaque materials. The near-field probe is a ap proximately 30 nm Ag particle, optically excited near the surface plas mon resonance frequency. The separation of the probe and sample is reg ulated by a Newton ring interferometer. The polarization rotation of t he scattered light due to near-field magneto-optic interactions is mea sured. A two-dimensional image is presented of thermomagnetically reco rded magnetic domains in a perpendicularly magnetized Co/Pt multilayer material with 0.5-mum-diam domains at one micrometer spacing. Images suggest a resolution of <100 nm.