SBIR Phase I: Growth of High Quality Optically Uniform CdGeAs2 Single Crystals by Horizontal Zone Melting

这个小企业创新研究第一阶段项目提出开发一种基于水平区熔化（HZM）的CdGeAs2单晶生长的新技术。CdGeAs2具有突出的光学非线性特性，是激光谐波产生和红外可调光源的最佳材料。然而，通过水平梯度冷冻生长的CdGeAs2晶体具有大量的光学不均匀区域，这限制了它们的使用。熔体体积的减小和HZM技术热场的轴对称有望产生改善成分均匀性的晶体。本课题拟开发一种基于HZM的生长技术，并将其应用于CdGeAs2的生长。利用快电子辐照可以生长出CdGeAs2单晶并提高其光透射率。晶体均匀性将用x射线、电学和光学测量来表征。最后，HZM生长的CdGeAs2晶体组成和质量均匀，将在光学参数振荡器中进行评估，以展示4至11 um的可调谐红外辐射。

This Small Business Innovation Research Phase I project proposes to develop a novel technique for the growth of CdGeAs2 single crystals based on Horizontal Zone Melting (HZM). CdGeAs2 has outstanding optical nonlinear properties, making it the best material for laser harmonic generation and tunable sources in the infrared. However, CdGeAs2 crystals grown by Horizontal Gradient Freeze have substantial optically non-uniform areas, which limits their use. The smaller volume of the melt and the axial symmetry of the thermal field of the HZM technique are expected to produce crystals of improved compositional uniformity.This project proposes to develop a growth technique based on HZM and apply it to the growth of CdGeAs2. CdGeAs2 single crystals will be grown and their optical transmission will be improved by irradiation with fast electrons. The crystal uniformity will be characterized using x-ray, electrical and optical measurements. Finally, HZM grown CdGeAs2 crystals of uniform composition and quality will be evaluated in an optical parametric oscillator to demonstrate tunable infrared radiation from 4 to 11 um.