Effect of Zirconium Content on Defect Structure and Light Damage Resistance of Zr:Dy:LiNbO3 Crystals

In this paper, Zr:Dy:LiNbO₃ crystals are prepared by traditional pull-up method, in which Zr⁴⁺ doping concentrations are 0, 1, 2, and 4 mol%, respectively. In this paper, the defective structure of Zr:Dy:LiNbO₃ crystals and their resistance to photodamage under different Zr⁴⁺ concentration doping are studied. Firstly, the influence of Zr⁴⁺ doping concentration on the defective structure of Zr:Dy:LiNbO₃ crystal and the occupancy of doped ions under different Zr⁴⁺ concentrations are tested and discussed by infrared (IR) absorption spectroscopy and ultraviolet-visible near-infrared (UV–vis–NIR) absorption spectroscopy. The Judd–Ofelt theoretical analysis results show that when the concentration of doped Zr⁴⁺ is 2 mol%, the spectral quality factor (X) of Dy³⁺ in lithium niobate crystals is significantly improved compared with that of Dy³⁺ in other crystals. Secondly, resistance to photodamage of Zr:Dy:LiNbO₃ crystals is studied and analyzed by the light scattering exposure energy flow threshold method. The results show that when the concentration of doped Zr⁴⁺ ions reaches 4 mol%, the exposure energy value is increased by 210 times compared with the no doping, which greatly improves the anti-photodamage performance of the crystal.