Growth and photorefractive properties of Mg, Fe co-doped near-stoichiometric lithium tantalate single crystals

Mg, Fe co-doped near-stoichiometric lithium tantalate (SLT) crystals were successfully grown by the zone-leveling Czochralski (ZLCz) technique and the holographic properties were measured by the two-beam coupling method. The fundamental optical properties of crystals were measured by employing the UV–vis–NIR spectrometer and Fourier transformation infrared spectrophotometer as well. By the chemical analysis, the Li/Ta, Mg/Ta and Fe/Ta ratios of the crystals were obtained and the Li/Ta ratios of the crystals were all close to the theoretical limitation of 0.98. In the holographic properties, the recording time constant, erasing time constant, dynamic range, and sensitivity decreased with light intensity; but the maximum diffraction efficiency showed an opposite trend. Furthermore, the diffraction efficiency, dynamic range and sensitivity of the crystals were improved with a relatively higher Fe/Ta ratio. In comparison with Mn–LT crystals, the Mg, Fe co-doped SLT crystal showed the superior photorefractive properties indicating that it could be a promising new material for lifetime holographic data storage.