Holographic measurements of optically induced refractive index inhomogeneities in bismuth titanate

Optically induced refractive index inhomogeneities (optical damage) in single crystal bismuth titanate (Bi 4 Ti 3 O 12 ) have been observed by the method of forming holograms inside the crystal. The maximum index change induced by light at 4880 A wavelength is approximately 10-5and lasts for a few minutes at room temperature.