The effect of crucible bottom deformation on the quality of Nd:GGG crystals grown by Czochralski method

Abstract

In this paper, we report the growth of neodymium doped Gadolinium Gallium Garnet (Nd:GGG) crystal using Czochralski (CZ) method, and study the effects of crucible bottom deformation and thermal insulator thickness on the growth process and crystal quality. Garnet structure and <111> crystallography orientation of the crystal were confirmed by the X-Ray diffraction (XRD) analysis. Macroscopic defects, residual stresses, quality, and homogeneity of the crystals were investigated by means of parallel plane polariscope and laser fizeau interferometer respectively and the results compared together. Experimental observations show that the crucible bottom deformation from flat to convex, and decreasing the thickness of zirconia insulator under the crucible result in the formation of lateral cores and increasing the crystal inhomogeneity and tensions, leading to the decrease of the crystal quality.

Growth of 60 mm-diameter Yb:CNGG single crystals with disordered coordination structure for high-energy laser systems

“…The uniformity of the as-grown Yb:CNGG crystal was comparable to that of the Nd:GGG crystal (2.61 × 10 −4 –7.73 × 10 −6 , PV = 0.30–4.70 λ ). 30 This suggests that the disordered coordination structure in Yb:CNGG does not result in the degradation of optical uniformity, providing a solid foundation for concrete lasing applications. In future studies, the optical uniformity of the Yb:CNGG crystal might be further improved by optimizing the growth process.…”