DESA emulsions have been developed at the TFH Berlin, University of Applied Sciences, in recent years. They represent an ultra-fine grained silver bromide emulsion system with mean grain sizes below 20 nm, which provides holographic recording in ultra-high resolution. Monochromatic sensitization has already been realized successfully for laser illumination in the whole optical wavelength range, reaching from blue (488 nm), via green (530 nm) up to red (632.8 nm). But panchromatic sensitization is handicapped by serious restrictions, if single-layer systems are used. Monochromatically sensitized materials are already on optimum level, which leaves little possibility to increase the sensitivity and diffraction efficiency further.
On the contrary, for panchromatic materials, the diffraction efficiency decreases normally if multiple exposures with different laser wavelengths are applied. The problem may be avoided by using multi-layer systems that are composed of monochromatically sensitized single-layers according to the different laser wavelengths as used by the multiple laser illuminations. In this case, excellent brightness and colour rendition should be obtained. This report gives a survey of the fundamentals and results of this new branch in DESA technology.
