These niobium oxides are exposed to air atmosphere resulting in pure Nb 2O 5. The complete protocol implies a LiH induced reduction of NbCl 5 followed by in situ spontaneous oxidation into low-valence niobium nano-oxides. Nanoparticles of lithium niobate and niobium pentoxide can be produced at low temperature. The technology is known as Lithium Niobate-On-Insulator (LNOI). for optical wave guides) can be grown on sapphire and other substrates, using the MOCVD process. Common orientations are Z-cut, X-cut, Y-cut, and cuts with rotated angles of the previous axes. Ī Z-cut, single crystal Lithium Niobate waferĪfter a crystal is grown, it is sliced into wafers of different orientation. Single crystals of lithium niobate can be grown using the Czochralski process. Other available dopants are iron, zinc, hafnium, copper, gadolinium, erbium, yttrium, manganese and boron. Lithium niobate can be doped by magnesium oxide, which increases its resistance to optical damage (also known as photorefractive damage) when doped above the optical damage threshold. It is transparent for wavelengths between 3 nanometers. Lithium niobate has negative uniaxial birefringence which depends slightly on the stoichiometry of the crystal and on temperature. It has a trigonal crystal system, which lacks inversion symmetry and displays ferroelectricity, the Pockels effect, the piezoelectric effect, photoelasticity and nonlinear optical polarizability. Lithium niobate is a colorless solid, and it is insoluble in water. 5 Periodically-poled lithium niobate (PPLN).