Nano-scale resolution optical pickup for reading/writing ultra-high density data on CD and DVD data storage elements

Abstract

A single high resolution holographic pickup, for reading/writing both a CD and DVD optical recording medium, has an electrical tuning control for applying a DC and AC signal to a tunable Bragg cell, which AC is phase locked with respect to the fundamental repetition frequency of the recorded data on the CD to produce accurate tracking. A special high resolution holographic lens is recorded within the Bragg cell that focuses the light signals read off of the optical storage mediums upon a pickup detector, and its focal length is varied to read a selected CD and or DVD from a group of CDs or DVDs in response to changes in the DC applied to the Bragg cell. The holographic lens within the Bragg cell is formed by an interference pattern produced by interfering light emitted from the tip of a one micron optical fiber and a plane broad light beam.

Dependencies are inferred from the claim text.