Abstract

Periodically poled LiTaO₃ has a shorter cut-off wavelength than KTP and LiNbO₃, which makes this material attractive for UV generation. However, the standard congruent material suffers strongly from photorefractive damage which has limited its use in the UV. It is expected that stoichiometric LiTaO₃ (SLT) would make a superior material in this context, as the defect concentration, which directly relates to the damage, is strongly reduced. Close to perfectly stoichiometric crystals can be obtained by post growth diffusion of Li₂O into the crystal at high temperatures to compensate the Li₂O deficiency, so called vapour transport equilibrated (VTE) SLT [1]. The coercive field is drastically reduced for SLT which also means that the domain structure of poled crystals gets less stable [2]. Moreover, VTE SLT shows very low photorefractive damage up to relatively high used intensities [3].

© 2015 IEEE