PVA photopolymer for classroom holography

Jeff Blyth
University of Cambridge, UK
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The author has been researching methods to produce a practical water-based photopolymer hologram recording system under red or green laser light. The remarkable ability of the dye methylene blue (MB) to fade to its colourless form under red light in the presence tertiary amines has been known for many decades. The author discovered during the 1980’s that this process could be much enhanced my incorporating the dye into a hydrophilic polymer that did not contain amine or amido groups ( as for example occur in gelatine and polyacrylamide), and also by including two tertiary amines with opposite charges. The author has now recently discovered how to use this system with a specific difunctional monomer mixed with polyvinyl alcohol, it has proved possible to make a coated glass sheet to record remarkably bright Denisyuk holograms for classroom demos with 633nm light with power as low as 7 mj/cm2 using nothing more than light and water as a post exposure treatment.

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