Nanoscale ridge aperture as near-field transducer for heat-assisted magnetic recording.

Near-field transducer based on nanoscale optical antenna has been shown to generate high transmission and strongly localized optical spots well below the diffraction limit. In this paper, nanoscale ridge aperture antenna is considered as near-field transducer for heat-assisted magnetic recording. The spot size and transmission efficiency produced by ridge aperture are numerically studied. We show that the ridge apertures in a bowtie or half-bowtie shape are capable of generating small optical spots as well as elongated optical spots with desired aspect ratios for magnetic recording. The transmission efficiency can be improved by adding grooves around the apertures.