Near-field optics is one of super-resolution techniques for future data storage system. We have already proposed a near-field optical flying head with a circular aperture. For realizing higher performance aperture, we developed a triangular one that has been experimentally evaluated with a scanning near-field optical microscope probe. By controlling the polarization of the incident light to the aperture, we could obtain a 100 nm resolution with a 190 nm-wide aperture. We also demonstrate the readout performance of this novel aperture mounted on a near-field head by introducing polarization control. To scan over a medium surface under a small-spacing condition, we fabricate a contact-type head having contact pads and a polarization maintaining fiber, because this type of aperture can only effectively function under a condition of both extremely small spacing and with applied polarized light. The head is fabricated mainly by photolithography. By controlling process conditions, we obtain contact pads at nm accuracy. A measurement of surface configuration using an interferometer shows that the aperture and the contact pads are almost on the same plane within 10 nm. The medium consists of a glass substrate, a titanium layer, a carbon protective layer, and a lubricant layer in this order. Line-and-space (L&S) patterns whose widths are 40-200 nm are formed on the titanium layer. The contact head approaches the medium surface, and then the medium is scanned by a piezo stage. The near-field light generated from the triangular aperture is scattered by the L&S pattern and detected by a photomultiplier tube. Signal readout from the 40 nm-wide L&S patterns is demonstrated with a 170 nm-wide triangular aperture.

A soft magnetic force microscope (MFM) tip was used to evaluate the magnetic recording characteristics of compositionally separated Co-Cr perpendicular media. Small magnetic bits were recorded on thick (350 nm). and thin (100 nm) films, focusing on the fineness of compositionally separated microstructures. MFM images showed bit marks 230 and 150 nm in diameter, measured at full-width at half maximum (FWHM) for the thick and thin films, respectively. These results verify that the recordable bit size can be decreased by using a thinner film with a finer compositionally separated microstructure. Simulation was used to clarify the relationship between the actual sizes of the recorded bits and the sizes of their MFM images. The recorded bit size was found to closely correspond to the FWHM of the MFM bit images.