Theoretical and experimental aspects of optical storage of information via refreshing by inverse seeding in a photorefractive Ba0.77Ca0.23TiO3 crystal (BCT)

We present a new experimental setup for the optical storage of information via refreshing by inverse seeding (OSIRIS), which allows a sixfold increase of the storage time of holograms in a Ba_0.77Ca_0.23TiO₃ crystal (BCT). The setup consists of two four-wave mixing processes with common amplified signal waves and phase-conjugated (pc) waves. Temporal behaviours of the amplified and pc signal waves for the OSIRIS experiment as well as for the common four-wave mixing experiment are compared and discussed. The solutions of coupled equations under the depleted-pump approximation are obtained in order to estimate the pc reflectivities and coupling gains of gratings inside the crystal. Received: 13 December 2000 / Revised version: 26 January 2001 / Published online: 27 April 2001