Nonvolatile hologram storage in near-stoichiometric LiNbO3:Tb, Fe

Near-stoichiometric LiNbO3:Tb, Fe crystals have three different types of energy levels suitable for two-color nonvolatile hologram recording. We investigated two-color multiplexed recording in the crystals. Hologram recording by use of 850nm recording beams and a gating fight of visible wavelengths starting from the UV-pre-exposed colored state was suitable for multiplexing. By taking into account the dynamic behavior of sensitivity and erasure time constant owing to the gradual decrease of UV-induced absorption during writing, we could record 100 multiplexed, hologram pages with nearly equal strength. An M/# of similar to0.33 was obtained and the multiplexed holograms showed very stable nonvolatile readout characteristics.