We investigate interband photorefraction in pure and Mg-doped near-stoichiometric LiTaO<sub>3</sub> at the deep ultraviolet wavelength of 257 nm. By controlling the stoichiometry, the response time and dynamic range of the interband photorefractive effect can be very much improved. Measured time constants are in the order of a few tens of milliseconds for UV light intensities of about 100 mW/cm<sup>2</sup>. Further, we report that Mg doping of near-stoichiometric LiTaO<sub>3</sub> increases the grating response rate by a factor of 50 compared with the one in undoped crystals. For UV light intensities larger than 500 mW/cm<sup>2</sup> the response time is faster than one millisecond. In Mg-doped near-stoichiometric LiTaO<sub>3</sub>, quasi-fixing of holographic gratings with UV light and nondestructive readout in the visible has been observed.

© 2005 Optical Society of America

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