Synthesis, Growth And Performance Of Rare Earth Doped Lithium Niobate Crystals

Lithium niobate (LiNbO3, LN) as an important multifunctional photoelectric material, due to its excellent piezoelectric, electro-optic, acousto-optic, thermoelectric, photorefractive and laser active and a series of special properties, are widely used in the infrared detector, integrated optical components, optical parameter oscillator, Q switch, etc. Especially in recent years, the solid state laser is widely used in medicine, laser ranging, and environmental monitoring, pure lithium niobate is a good laser doping matrix material, but in the process of growth, lithium loss by volatilization, causes of lithium niobate crystal growth is in a state of lack of lithium, resulting in LN crystals in the presence of large amounts of space. And its performance has a great influence, so nearly stoichiometric ratio of LiNbO3 crystal growth is very necessary.In this paper, near the stoichiometric ratio high quality rare earth holmium and thulium-doped lithium niobate single crystal are grown by Czochralski in the lithium-rich environment, the transmittance was more than 75% in the visible light region. The mechanical properties of LiNbO3 near stoichiometric ratio were compared in different directions, the Vickers hardness tester indenter at LiNbO3 (006) sample surface have the indentation deeper and longer crack (300) sample surface under 0.1kg load, by the measurement and calculation, (300) plane of the sample Vickers hardness value of 629.6 kg mm-2 was significantly higher (006) plane of 473.4 kg mm-2, while by measuring the (300) plane and the (006) plane fracture toughness, brittleness index and elastic modulus, which show that (300) surface mechanical properties than LiNbO3 (006) better observe the stress distribution under stress analyzer both found (300) stress distribution ratio (006) plane more little more evenly. The upconversion luminescence spectra of Ho3+ doped near stoichiometric ratio LiNbO3 crystal are tested at 655nm excitation. It analyzes the relationship upconversion luminescence peak position and intensity of Ho3+ doping concentration, and analyzes the conversion mechanism Ho3+ in it. But also it has been done on the Tm3+:LiNbO3 crystal with 808nm light excitation, explaining the conversion mechanism of and analyze the doping concentration and intensity of the impact, the color coordinates of the sample have been compared with different doped concentration, while the Ho3+ and Tm3+ doped near stoichiometric ratio LiNbO3 crystal powder are analyzed and found at 655nm and 808nm excitation respectively can emit stable and bright green and red.