Domain growth in LiNbO₃ with surface layer modified by soft proton exchange

Abstract

We present the study of domain growth in congruent LiNbO₃ crystals with planar soft proton exchanged waveguides (CLN SPE). The spatial distribution of H ions was measured by confocal Raman microscopy. The growth of elongated irregular shape domains followed by slow domain widening was obtained. Domain approaching led to a change in the growth directions. Domain widening represented formation of submicron domains with depth of tens microns in front of the domain walls. Low threshold field is attributed to the surface composition gradient. The suppression of hexagonal domain growth is related to existence of the surface dielectric layer.

Keywords:

• Lithium niobate
• proton exchange
• polarization reversal
• domain shape
• correlated nucleation

Acknowledgments

The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University (registration number 2968) was used.

Additional information

Funding

The reported study was funded by RFBR (project 20-32-90192) the Ministry of Science and Higher Education of the Russian Federation (projects 075-15-2021-677 and FEUZ-2020-0054).