Copying reflection gratings in silver halide and dichromated gelatin

The copying of holograms from one plate or material to another has been studied for several years. Copying allows a practical and flexible method for the reproduction of holographic optical elements (HOEs) or diffuse wave holograms. Contact interference copying has high stability and does not require strict coherence requirements from the light source. This is advantageous for copying into the material dichromated gelatin (DCG) which has a relatively low sensitivity compared with that of silver halide (AgH⁺). The authors present some experimental results of copying reflection gratings of varying modulation between DCG master and DCG copy, DCG master an AgH⁺ copy and AgH⁺ master with DCG copy, all using the contact interference technique