A numerical study on the effect of temperature gradient on the growth stability of Yb:YAG crystals grown using the EFG method

Abstract

This study focuses on the edge-defined film-fed growth (EFG) method for growing Yb:YAG crystals, analyzing the relationships among insulation structures, temperature gradients, and the driving force for crystal growth. We investigated the temperature field through 3D numerical simulation and examined how different insulation thicknesses modulate the axial temperature gradient near the die top and the radial temperature distribution on the die top surface. By incorporating the axial temperature gradient into the pressure and heat balance equations at the meniscus, we derive the limiting ranges of the process parameters, which provide guidance for successfully growing high-quality crystals. Subsequent measurements of X-ray excited luminescence (XEL) spectra and decay times revealed that the luminescence characteristics of the EFG-grown crystals are comparable to those of crystals grown by the Czochralski (Cz) method.