BEAM FOCUSING IN NEAR-FIELD OPTICAL RECORDING AND READING

摘要

A near-field optical storage system having an optical train configured to produce a reduced beam spot size at the recording layer of an optical medium. A near-field coupling element having a substantially flat surface is implemented to provide optical coupling between the optical train and the optical medium. The flat surface is spaced from the optical medium by a fraction of the operating wavelength. An optical beam is focused beyond the flat surface in order to achieve a small spot size on the recording layer.