Lithium niobate single-crystal and photo-functional device

摘要

Provided are lithium niobate single-crystal that requires a low voltage of not larger than 10 kV/nm for its ferroelectric polarization inversion and of which the polarization can be periodically inverted with accuracy even at such a low voltage, and a photo-functional device comprising the crystal. The crystal has a molar fraction of Li2O/(Nb2O5+Li2O) of falling between 0.49 and 0.52. The photo-functional device can convert a laser ray being incident thereon.