Abstract Single crystal quality is a key issue for optical applications. Indeed, in optical frequency conversion processes, defects in single crystals can drastically decrease the conversion yield. The study of the quality of an AgGaGeS4 single crystal is presented in this work. Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-Ray Spectroscopy (EDS) was used to perform a chemical analysis mapping of a large size single crystal cut (surface 26 × 20 mm2). Chemical inhomogeneity was found along the crystal growth axes and confirmed by optical characterization showing laser beam perturbations. Compounds volatility, lack of melt homogenization and instability of crystallization front might explain this chemical inhomogeneity. Solutions to improve the crystal growth process and enhance the crystal’s quality are finally proposed.

中文翻译：

---

用于非线性中红外激光应用的单晶 AgGaGeS4 的均匀性表征

摘要 单晶质量是光学应用的关键问题。事实上，在光频转换过程中，单晶中的缺陷会大大降低转换产率。这项工作介绍了 AgGaGeS4 单晶的质量研究。使用扫描电子显微镜 (SEM) 结合能量色散 X 射线光谱 (EDS) 对大尺寸单晶切割（表面 26 × 20 mm2）进行化学分析映射。沿晶体生长轴发现了化学不均匀性，并通过显示激光束扰动的光学特性证实了这一点。化合物的挥发性、熔体不均匀化和结晶前沿的不稳定性可能解释了这种化学不均匀性。最后提出了改善晶体生长过程和提高晶体质量的解决方案。