SIMPLIFIED METHOD FOR PREPARING METHYLENE-BLUE-SENSITIZED DICHROMATEDGELATIN

Methylene-blue-sensitized dichromated gelatin (MBDCG) is a suitable ma terial for recording full-color holograms in a single layer. However, a drying process in an ammonia atmosphere is necessary to prepare the MBDCG plate. This process is time-consuming and unstable. A simplified method for preparing the MBDCG plate is presented in which the MBDCG can be dried without ammonia. Elimination of the drying process is pos sible when the methylene blue in MBDCG does not separate. This is achi eved by a decrease in the concentration of dichromate in the photosens itized solution and the addition of an ammonia solution to the photose nsitized solution. Last, the gelatin is allowed to gel. A Lippmann col or hologram grating with a diffraction efficiency of more than 80% is obtained by use of this MBDCG. (C) 1998 Optical Society of America.