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The authors describe a technique for fabricating submicron domain inversion structures in MgO:LiNbO3. The method is based on controlled backswitched poling with short voltage pulses. Using this method, short periodic structures consisting of submicron domain patterns have been achieved in Z-cut MgLN crystal. The structure is fully compatible with nonlinear optical integrated waveguide applications. High performance of the submicron domain inversion structure is also demonstrated by evaluating its potential as second harmonic generation. [ABSTRACT FROM AUTHOR]

Photorefractive properties of congruent lithium niobate crystals codoped with HfO2 and Fe2O3 were investigated and it was found that Fe ions are still located at Li sites as photorefractive centers when the doping concentration of HfO2 goes above the threshold value. As a result, their photorefractive response speed and sensitivity are significantly enhanced. Meanwhile, the high saturation diffraction efficiency is still maintained. Experimental results definitely show that Hf is now the most effective doping element for LiNbO3:Fe crystal to improve its photorefractive properties. [ABSTRACT FROM AUTHOR]

We investigated the light-induced backward scattering in doubly doped lithium niobate crystals and observed an intensity threshold effect. It will be shown that scattering microregions are locally recorded in the sample by holographic interaction due to the existence of the threshold effect. Experimental results of multilayer recording point out that this property could be used for high-density multilayer-like bit data optical storage while keeping high signal-to-noise ratio. [ABSTRACT FROM AUTHOR]

A method to determine the focal length of a thermal lens and pumping laser beam waist in the gain medium in laser-diode-pumped solid-state lasers is presented. This method, using resonator transform circle theory, is both simple and reliable. The measured focal length of the thermal lens is used to calculate the beam waist of pumping laser inside the gain medium. The effect of the thermal lens on the output power is also measured and analyzed. [ABSTRACT FROM AUTHOR]

LiNbO[sub 3] crystals with a composition close to stoichiometry were prepared by using a vapor transport equilibration (VTE) technique. The influence of the intrinsic defect density in the electric field periodic poling LiNbO[sub 3] crystal is studied. The switching field is found to decrease with the intrinsic defects. The reduction of intrinsic defects is mainly due to a change in the Li/Nb ratio in the LiNbO[sub 3] crystal, as a result of lithium diffusion during the VTE process. The switching field of ∼2 kV/mm in stoichiometric LiNbO[sub 3] is about one fourth of the previously published results obtained with near-stoichiometric crystals, and is approximately one tenth of the conventional congruent field. Periodic poling of thicker stoichiometric substrates was successfully performed by means of an electric field poling process at room temperature. [ABSTRACT FROM AUTHOR]

This letter reports three new absorption steps appearing by the long wavelength side of the UV intrinsic absorption edge of β-BaB[sub 2]O[sub 4] crystal at low temperatures We suggest that these new absorption steps should be attributed to the transitions of the indirect excitons bound in the centers of certain neutral impurities contained in the crystal specimens. [ABSTRACT FROM AUTHOR]