Domain Structure Fabrication in Z and Y-cuts of LiTaO3 Crystals by Point e-beam Writing in the SEM

Abstract

In this work, a set of local electron irradiations has been used to fabricate domain gratings in conventional lithium tantalate crystals. The Z and Y-cuts of the crystals were irradiated in the SEM at 25 kV, using different distributions of square point writing by an e-beam. Peculiarities of the domain-inverted gratings that were located near the surface of the Y- cuts and in the crystal bulk of the Z-cuts have been investigated at the different drawing motives, doses of irradiations and crystallographic directions of e-beam movement during writing. The domain structures were examined in optical microscopes after chemical etching of the irradiated samples. The crystallographic Y directions were found to be important in e-beam drawing on Z-cut surfaces. Account should be taken of the crystallographic Z direction during e-beam writing and long domain-inverted grating fabrication on the Y-cuts. For both polar cuts, the reduction of intervals between the sequences of local irradiated areas down to 2–3 μm was observed to facilitate polarization switching as compared to the case of 15 μm intervals between the square points. At these smaller intervals, domains of the same lengths were formed at electron irradiation doses several times lower.