Single crystals of Bi12TiO20 (BTO) are grown by a modified Czochralski technique. Doping with cadmium, calcium, gallium, and vanadium is performed by adding corresponding oxides to the melt. Optical parameters like refractive index, optical absorption, optical activity, light induced absorption, electrooptic coefficient, and photoconductivity are determined. Photorefractive properties of the samples are characterized with the help of a conventional two-beam interference setup. Diffraction efficiency and decay time constant of elementary holograms are determined. The influence of the utilized dopands is discussed.

Photorefractive planar waveguides in LiNbO3 are fabricated by a combined proton and copper exchange. The dependence of refractive index profiles, optical absorption, and electrooptic coefficients on different fabrication steps is investigated. With holographic methods dark and photoconductivity, holographic sensitivity, and light‐induced refractive index change in the waveguides are measured. By the additional copper exchange the steady state diffraction efficiency of holographic gratings in our proton‐exchanged waveguides is increased from 0.01 to 65%.

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Recording of holographic gratings in z-cut LiNbO(3) waveguides with extraordinarily (TM) polarized light is demonstrated. In this geometry, photovoltaic currents perpendicular to the guiding layer and the grating vector set up space-charge fields. The mechanism has no equivalent in bulk material.

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Holographic gratings were thermally fixed in iron-doped photorefractive LiNbO(3) crystals and developed with frequency-doubled Q -switched pulses of a Nd:YAG laser (light wavelength, 532 nm; pulse duration, 3 ns). The saturation values of the diffraction efficiency increased with increasing pulse light intensity. Compared with development with cw light, high-intensity laser pulse development resulted in an enlargement of the diffraction efficiency of a factor of ~2 . A contribution of the intrinsic defect Nb on Li site to the charge transport is most probably the origin of this effect. The results are useful, e.g., for improvements of volume holographic memories and wavelength filters.

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