New method of making HOE by copying CGH on NGD

In this paper it is presented that holographic optical elements (HOEs) generated by computer are copied on nongelatin dichromated holographic films (NGD) [1,2], which has a characteristic of controlling groove profile and copying easily etc. This may be a new method to fabricate HOEs with continuous phase modulation. The diffraction efficiency of the HOEs on NGD, e.g., NGDHOE, has been increased over three times comparing with that of original CGH reduced—photographed and bleached. The depth of relief patterns can be controlled by exposure. It is indicated that ti'e final NGDHOE can be used as a master of embossment directly in plastic film. This would be an efficient way that to produce cheaper and lighter weight HOEs in large scale. KEYWORDS: CGH, NGD, HOE, etching, blazing grating