High-numerical-aperture lens system for optical storage

Abstract

We describe a new type of optical pickup for use in high-density optical storage systems. By changing a conventional pickup design to include a glass element between the objective and the disk, the transverse resolution of the system can be increased by as much as a factor of 1.5. This system is also less sensitive than conventional systems to variations in disk thickness and disk tilt. We demonstrate how the system has been used as a microscope to inspect an optical disk and describe possible design configurations for an optical pickup.