We describe a two-center holographic recording method for the storage of pe
rsistent holograms in doubly doped lithium niobate crystals. We use a two-c
enter model, and we show that our experimental observations can be explaine
d by the model. We describe experimental methods for finding the unknown ma
terial parameters of LiNbO3:Fe:Mn crystals for the two-center model, and we
discuss the optimization of two-center recording. (C) 2001 Optical Society
of America.