The dynamic recording range or the maximum index modulation obtainable in any holographic material limits the properties of the hologram. The product of the modulation times the thickness determines diffraction efficiency in any phase hologram. In a reflection hologram low uniform modulation yields narrow spectral and angular bandwidths and high modulation in a chirped structure yields high angular and spectral bandwidths. An ideal master hologram requires a just right efficiency and very low noise to produce the best possible copies. In a two beam copy scheme the efficiency is less important than the low noise because beams can usually be balanced to the just right range with a variable beam splitter. In a single beam copy scheme the balance and the low noise plus wide enough angular and spectral responses all have to be built into the master. DCG has all the right properties for a top quality master that will get the most from any copy film of marginal index modulation, single beam reflection copies in Dupont photopolymers are as bright as the material will allow in any copy configuration.
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