Flexible monolithic optical head slider combined with visible laser light guide for first surface optical recording

Abstract

Optical near-field recording is a candidate technology for overcoming the diffraction limit of conventional optical recording. In our previous work, we proposed a novel optical head slider for near-field recording that we call a flexible optical head slider. An air-bearing pad pattern is formed on the apex of a cantilever-like polymeric waveguide so that, by using the cantilever itself as the slider suspension, a single body structure incorporates the functions of the flying slider, suspension, and waveguide. This structure can be expected to provide several important advantages by miniaturizing head assemblies; simplifying the assembly and optical trimming processes; and producing a lighter head, thus allowing a wider tracking bandwidth. In our previous report, the mechanical characteristics and readout signal characteristics of the flexible head slider were evaluated. In this paper, we studied the tracking control for the flexible optical head slider. To detect tracking errors, a T-shaped aperture was used. One straight part of the T-shaped aperture was set along the edge of the tracks, so the transmitted light from this part is sensitively affected by off-track displacement. Another straight part is used for readout of the data marks. The T-shaped aperture was formed through the metal layer deposited on the slider pad surface, at the end of the waveguide core, using FIB (focused ion beam) etching. Test ROM media with repeated pattern of 0.5 micron-sized dot marks was used to evaluate the position error signal.