Optimized growth of high length-to-diameter ratio Lu2O3 single crystal fibers by the LHPG method

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers. Lu2O3 single crystal fibers (SCFs) with a length-to-diameter ratio of >200 : 1 were successfully grown by the laser heated pedestal growth (LHPG) method for the first time. The relationships between the crystal diameter and thermal stress were investigated in detail. Crystal cracking was effectively solved by reducing the diameter of the crystal fiber. Besides, the influence of the growth atmosphere on the crystal growth was also demonstrated. The crystals grown in a mixture of 95% O2 and 5% Ar were colorless and transparent. The XRD pattern showed that the phase of Lu2O3 was pure, and the crystal quality along the axial and radial directions was measured by Laue back-reflection measurements. Meanwhile, the diameter fluctuations of the obtained Lu2O3 crystal fibers were further reduced by using optimized source rods.