75-MHz data-transfer rate with a planar aperture mounted upon a near-field optical slider

We fabricated a planar aperture–mounted (PAM) slider by use of a focused ion beam to demonstrate fast data acquisition for near-field optical data storage. The aperture $\left(200 \mathrm{nm}\times 500 \mathrm{nm}\right)$ was formed upon the Ti-coated air-bearing surface of the slider and was directly illuminated with a laser $\left(\lambda =532 \mathrm{nm}\right)$ beam spot by use of an objective lens $\left(\mathrm{N}.\mathrm{A}.,0.55\right)$. The light transmitted through the aperture was modulated by a Ti-coated ${\mathrm{SiO}}_2$ disk with 200- and 400-nm-wide line-and-space (L&S) patterns engraved by electron-beam lithography. The optical throughput of the taperless aperture was greater than 0.02. By use of the PAM slider, 400- and 200-nm L&S signals were detected at linear velocities of 6 and $3 \mathrm{m}/\mathrm{s}$, respectively, corresponding to a data-transfer rate of 7.5 MHz.