Method for Holographic Mastering and Replication

Abstract

A method for producing holograms with a multiplicity of holographic prescriptions from a single master is provided. A multiplicity of holographic substrates each containing a first hologram is stacked on a second holographic recording medium substrate. The first hologram is designed to diffract light from a first direction into a second direction. When expose to illumination from the first direction zero order and diffracted light from each first hologram interfere in the second holographic recording medium substrate forming a second hologram. The second hologram is then copied into a third holographic recording medium substrate to provide the final copy hologram.

1 . A method for producing a pluarlity of holograms with a plurality of prescriptions from common master hologram, the method comprising:
 providing a master hologram configured to provide diffracted and zero-order beams angles for each of a plurality of incident beam directions;   providing an intermediate holographic medium;   providing a contact copy holographic medium;   providing a light source to provide a plurality of incidence angles on said master hologram;   illuminating said master hologram with a light of a first polarization in a first direction;   diffracting said light into a zero order beam in said first direction and a diffracted beam in said second direction using said master hologram;   interfering said zero order beam and said diffracted beam in said intermediate holographic medium to form an intermediate master hologram;   placing said intermediate master hologram in contact with said contact copy holographic medium;   further illuminating an external surface of said intermediate master hologram with a second light in said first direction, said intermediate master hologram diffracting said second light into a second zero order beam in said first direction and a second diffracted beam in said second direction, said second diffracted and second first order beams interfering in said contact copy holographic medium to form a contact copy hologram.   
     
     
         2 . The method of  claim 1 , wherein said steps of illuminating, diffracting, interfering, placing and further illuminating are repeated for a multiplicity of values of said first and second directions. 
     
     
         3 . The method of  claim 1 , wherein the first and second directions falls within the diffraction efficiency angular bandwidth of said master hologram. 
     
     
         4 . The method of  claim 1 , wherein the master hologram is provided by the steps of:
 configuring a laser holographic recording apparatus to form a first recording beam in said first direction and a second recording beam in said second direction;   providing N substrates each containing a master holographic medium; and   interfering said first and second beams within each said master holographic medium substrate to form a first hologram in each said substrate.   
     
     
         5 . The method of  claim 1 , where said master hologram includes at least one selected from the group consisting of: a liquid crystal and polymer material system, a holographic photopolymer, and a surface relief grating. 
     
     
         6 . The method of  claim 1 , wherein said master hologram has a modulation exceeding that required to achieve a target beam ratio of said diffracted and zero order beams. 
     
     
         7 . The method of  claim 1 , wherein said master hologram has a modulation exceeding by up to 5% that required to achieve a target beam ratio of said diffracted and zero order beams. 
     
     
         8 . The method of  claim 1 , wherein said master hologram has a modulation exceeding by up to 10% that required to achieve a target beam ratio of said diffracted and zero order beams. 
     
     
         9 . The method of  claim 1 , further comprising providing one of either a half wave plate and a linear polarizer and disposing it between said intermediate holographic medium and said master hologram. 
     
     
         10 . The method of  claim 1 , wherein said contact copy hologram is a copy of said intermediate master hologram and said intermediate master hologram is a copy of said master hologram. 
     
     
         11 . The method of  claim 1 , wherein said zero order and diffracted beams in at least one of the diffracting or further illuminating steps have power substantially in the ratio of 1:1. 
     
     
         12 . The method of  claim 1 , wherein said intermediate master hologram and said contact copy holographic medium are separated by an air gap. 
     
     
         13 . The method of  claim 1 , wherein at least one index matching optical layer is provided. 
     
     
         14 . The method of  claim 1 , wherein said contact copy holographic medium forms part of a mechanically translatable continuous lamina. 
     
     
         15 . The method of  claim 1 , further comprising providing a voltage generator for applied a voltage across at least one of said intermediate holographic medium and said contact copy holographic medium characterized in that said voltage varies the refractive index modulation of at least one of said intermediate master hologram and said contact copy hologram during the further illuminating. 
     
     
         16 . The method of  claim 1 , further comprising providing a voltage generator for applied a voltage across said master hologram characterized in that said voltage varies the refractive index modulation of said master hologram during the illuminating, diffracting and interfering steps. 
     
     
         17 . The method of  claim 1 , wherein the at least one medium selected from the group of said intermediate holographic medium and said contact copy holographic medium is one of a material selected from the group of a photo thermal refractive or photopolymer, a forward mode HPDLC mixture or a reverse mode HPDLC mixture. 
     
     
         18 . The method of  claim 1 ,
 wherein said intermediate holographic medium and contact copy holographic medium are supported by one of either a glass or a plastic substrate.   
     
     
         19 . The method of  claim 1 , wherein said intermediate holograhic medium and contact copy holographic medium are supported by substrates. 
     
     
         20 . The method of  claim 1 , wherein said contact copy hologram forms part of a waveguide.