High Spatial Resolution and Throughput Potential of an Optical Head with a Triangular Aperture for Near-Field Optical Data Storage

A near-field optical head with a triangular aperture has been precisely analyzed on the basis of a three-dimensional finite-difference time-domain method in order to obtain both higher spatial resolution and signal output performance for a near-field optical data storage system. The numerical analysis revealed that in contrast to a conventional aperture, this triangular-shaped aperture can successfully enhance energy distribution intensity at only the side perpendicular to the incident polarization direction, generating an extremely small optical spot not limited by its entire aperture size. The read-out performance was also simulated for the aperture passing over a space-patterned metal medium, resulting in both superior spatial resolution and signal output.