Intensity dependence of two-colour holographic recording and hologram multiplexing in Tb-doped near-stoichiometric LiNbO3

Two-colour holograms were recorded in a Tb-doped near-stoichiometric LiNbO3 crystal by use of extraordinary 778 nm beams for writing and an ordinary 350 nm beam for gating. The dependences of two-colour recording sensitivity and the saturated diffraction efficiency on the intensities of the recording and gating beams are presented. The saturated diffraction efficiency increased with total writing intensity, and then reached a saturated value of 56% at an intensity of 20 W cm−2. The sensitivity increased linearly with gating intensity at low intensity, and then saturated with a value of 0.08 cm J−1 at an intensity of 1.6 W cm−2. Fifty plane-wave holograms are recorded by the angle-multiplexing method and an M/# of 1.13 is obtained.