Holographic digital data storage system compatible with a CD/DVD player

Abstract

The holographic digital data storage system is compatible with a CD/DVD player. A polarization direction of the beam is altered by a first wave plate and the size of the polarized beam is expanded by a beam expander. The expanded beam is split into a vertical polarized beam and a horizontal polarized beam by a polarization splitter; a polarization direction of the horizontal polarized beam is altered by a second wave plate. An optical path of the vertical polarized beam is adjusted by a first mirror to generate a first path-controlled beam; an optical path of a third directional polarized beam is controlled by a second mirror to generate a second path-controlled beam; the first and the second path-controlled beams are concentrated by using a first and a second lenses, respectively; and the interference of two beams is recorded on a medium.

What is claimed is:  
     
         1 . A holographic digital data storage system compatible with a CD/DVD player, comprising: 
 a light source for generating a beam;    a first wave plate for altering a polarization direction of the beam to a predetermined direction to generate a polarized beam;    a beam expander, disposed to confront with the first wave plate, for expanding the size of the polarized beam;    a polarization splitter for splitting the expanded beam into a vertical polarized beam, vertical to the polarization direction, and a horizontal polarized beam, horizontal to the polarization direction;    a second wave plate for altering a polarization direction of the horizontal polarized beam to another predetermined direction to generate a third directional polarized beam;    a first mirror for adjusting an optical path of the vertical polarized beam to generate a first path-controlled beam;    a second mirror for controlling an optical path of the third directional polarized beam to generate a second path-controlled beam;    a first and a second lenses for concentrating the first and the second path-controlled beams, respectively, to generate a first and a second concentrated beams; and    a medium for recording the interference of the first and the second concentrated beams.    
     
     
         2 . The holographic digital data storage system of  claim 1 , wherein the beam is a laser beam.  
     
     
         3 . The holographic digital data storage system of  claim 1 , wherein the medium includes a substrate, a holographic digital data storage material and a mirror coating material sandwiched between the substrate and the holographic digital data storage material.  
     
     
         4 . The holographic digital data storage system of  claim 1 , wherein the second mirror is a micro-mirror array with a plurality of mirror pixels for forming a plurality of optical channels.  
     
     
         5 . A holographic digital data storage system compatible with a CD/DVD player comprising: 
 a light source for generating a beam;    a first wave plate for altering a polarization direction of the beam to a predetermined direction to generate a polarized beam;    a polarization splitter for splitting the polarized beam into a reference beam and a signal beam;    a second wave plate, located at a forward reflection terminal of the polarization splitter, for adjusting the reference beam so that a reconstructed signal beam of the signal beam in the holographic digital data storage system mode is transmitted through the polarization splitter;    a third wave plate, located at a transmission terminal of the polarization splitter, for controlling the signal beam so that a reconstructed signal beam of the signal beam is reflected by the polarization splitter in the CD/DVD player mode;    a spatial light modulator for adjusting numerical aperture by an on-off operation on a pixel basis in the CD/DVD player mode;    a medium for recording the interference of the reference and the signal beams; and    means for, located at the backward reflection terminal of the polarization splitter, displaying the reconstructed signal beam.