Influence Of Dopant Concentration On The Spectroscopy Performances In Mg²⁺ Doped?0,4,5 And 6 Mol%? Dy:LiNbO₃ Crystal

A series of Dy: LiNbO₃ crystals with x mol% Mg²⁺ions?x=0,4,5 and 6 mol %?were grown by Czochralski method.The influence of the various dopant concentrations of Mg²⁺ions on the defect structure,UV-Vis-NIR spectroscopy and the optical damage resistance of Mg: Dy :LiNbO₃ crystal.The distribution coefficient of Mg²⁺ and Dy³⁺ ions was studied by the inductively coupled plasma-atomic emission spectrometry?ICP-AES?.When the concentration of Mg²⁺ ions is lower than its threshold value,Mg²⁺ replace4LiNb?10?,formingLiMg?10?defects.When the concentration of Mg²⁺ ions exceeds its threshold value,4LiNb?10?were completely replaced by Mg²⁺ ions.Meanwhile,the Mg²⁺ occupy to the normal Li sites and Nb sites formingLiMg?10?and3NbMg-.The surface the Mg:Dy: LiNbO₃ is very smooth and practically free of droplets as highlighted by atomic force microscopy?AFM?.The root-mean-square?rms?surface roughness of the sample Mg?4mol%?: Dy: LiNbO₃ was determined to be 14.758 nm.The UV-Vis-NIR absorption spectra of Mg: Dy: LiNbO₃ crystals have been evaluated to predict the spectroscopic properties by using the Judd-Ofelt theory.J-O intensity parameters have been obtained: ?₂=7.53×10^-20 cm²,?₄ = 6.98×10^-20 cm²,and ?₆=3.09×10^-20 cm² for Mg:?6 mol%?Dy: LiNbO₃ crystals.In comparison with some other reported Dy-doped crystals,a larger spectroscopic quality parameter?X=2.26?is found in Mg:?6 mol%?Dy: LiNbO₃ crystal.The optical damage resistance ability of Mg: Dy: LiNbO₃ crystals were studied by light-induced scattering exposure energy flux threshold method and it increases with the concentration of Mg²⁺ ions.When the concentration of Mg²⁺ ions is 6mol%in the melt?the sample Mg-6?,the exposure energy achieves 709.27 J/cm²,approximately 320 folds than that of the sample Mg-0 in magnitude.The experiment results show that a series of Mg: Dy: LiNbO₃ crystals were observed to be smooth cracks,and the Mg:?6 mol%?Dy: LiNbO₃ crystal possesses excellent optical properties and optical damage resistance.