Angle-multiplexed hologram storage in LiNbO3 : Tb, Fe

We have performed hologram multiplexing with a cw laser at lambda = 532 nm in a near-stoichiometric LiNbO3:Tb,Fe crystal that exhibits a visible absor ption band induced by UV light. When 50 plane-wave holograms were angle mul tiplexed from the UV preexposed state, the recording sensitivity gradually decreased, owing to bleaching of the induced absorption. However, a convent ional recording schedule of multiplexing many holograms of equal diffractio n efficiency can be used in this photochromic material. The gradual decreas e in recording sensitivity throughout multiplexing can be compensated for b y the increased erasure-time constants of later-written holograms. An M/# o f 1.73 was obtained in a crystal of 3.3-mm thickness. (C) 2000 Optical Soci ety of America.