An aqueous photopolymer for classroom holography

Abstract

An aqueous photopolymer possessing good photosensitivity for recording holograms in red laser light is described. This development follows the author’s earlier discovery of the enhancing effects of an acid-base amine combination used as a free-radical producing co-initiator with methylene blue dye to polymerise suitable monomers. The system also works with green laser light using the dye safranine-O. After exposure, the image develops in water. With this photopolymer, individual students in a classroom can use small cheap red laser pointers with their collimating lenses cut off to make simple Denisyuk holograms under subdued lighting. As the polymer is water-based, its preparation in a school lab is feasible.

Keywords:

• aqueous photopolymer
• classroom holography
• methylene blue
• safranine-O
• amine co-initiators

The author is grateful for the sponsorship of the Holography Group of the Royal Photographic Society, which enabled him to participate in the Eighth International Symposium on Display Holography held in Shenzhen, China, in July 2009, where he presented a preliminary version of this paper. He is also indebted to Dr Samuel Michel of Kuraray Europe GmbH (Frankfurt am Main, Germany), for generous donations of various grades of PVA. He also owes a debt to his friend and colleague Dr Colin Davidson from the Institute of Biotechnology, Cambridge University, who brought in his own digital photographic equipment to make picture and film sequences, for his help and support in this research.