Non-volatile volume holograms in bismuth tellurite crystals with nanosecond laser pulses

Bismuth tellurite is a promising photorefractive material for holographic data storage. Due to its self-fixing capabilities bismuth tellurite does not require any further fixing technique and hence enables non-volatile read-out of recorded holograms. Basically the effect is accomplished by converting the electro-optically induced refractive index modulation into an electrically neutral modulation of the spatial oxygen distribution. Two dimensional datapages are recorded in an undoped bismuth tellurite crystal using a pulsed Nd:YAG Laser at 532 nm with pulse durations in the nanosecond time scale. Build-up, decay and diffraction efficiency of the photorefractive gratings are studied under pulse excitation. Furthermore we compare the quality, durability and bit error rate of recorded digital datapages with those stored in iron doped lithium-niobate crystals.