Investigation of Defect Structure and Optical Properties of Sc: Yb: Ho: LiNbO3 Crystals with Different [Li]/[Nb] Ratios

Sc: Yb: Ho: LiNbO3 crystals with various [Li]/[Nb] ratios (0.85, 0.94, 1.05, 1.20 and 1.38) were grown by Czochralski method. In this report, the effect of the [Li]/[Nb] ratio dependence of the doped element concentration and segregation coefficient was studied using an inductive coupled plasma-atomic emission spectrometer (ICP-AES). It was found that the change of the [Li]/[Nb] ratio will affect the concentration and the occupancy of the doped ions in the crystal. The structures of the crystals with different [Li]/[Nb] ratios are analyzed using X-ray diffraction patterns (XRD). It was found that doping elements do not change the crystal structure, and the crystal has the least defects when the [Li]/[Nb] ratio is 1.20. The optical uniformity of crystals was measured by birefringence gradient method. The results show that the optical uniformity of the crystal is significantly enhanced as the [Li]/[Nb] ratio increases.