新型黄光晶体Dy,Tb:GdScO3的生长及激光性能研究

Yellow laser has important application in biomedical, laser guide star, laser display, and so on. The way of realizing yellow laser by LD directly pumped laser crystal has many advantages such as small volume, good stability, low noise. So far, only Dy:YAG crystal belonging to oxides realized Dy yellow laser, but the power and efficiency are both very low. Compared with YAG, GdScO3 is easier to realize yellow laser, because of its lower phonon energy, larger birefringence, and lower crystal symmetry. Applicants found that Dy:GdScO3 has broader absorption FWHM, larger absorption and emission cross sections and that energy transfer is realized through Dy and Tb codoping, which can shorten the long lifetime of lower laser level in Dy doped crystal. Besides, applicants found the absorption and emission cross section increased by Dy and Tb codoping. The main work is to grow high-quality Dy and Tb codoped GdScO3 single crystal by Cz method, and study the scheme of energy transfer in Dy,Tb doped GdScO3. Finally, it is expected to obtain efficient and stable yellow laser, and provide working substance for the development of solid state yellow laser.

黄光激光在生物医疗、激光钠导星、激光显示等领域具有重要应用。采用LD直接抽运激光晶体实现黄光激光无需进行非线性频率变换，具有体积小、稳定性好、噪声低等优点。目前实现Dy黄光输出的氧化物激光晶体仅有Dy:YAG，但效率及功率都很低。与YAG相比，GdScO3晶体具有较低的声子能量，较大的双折射和较低的晶体对称性，更易实现激光输出。申请者发现Dy:GdScO3具有比Dy:YAG更大的吸收半高宽、吸收和受激发射截面，并且通过Dy,Tb共掺，实现了能量共振转移，可解决Dy单掺晶体激光下能级寿命长的问题。另外，还发现通过Dy,Tb共掺进一步提高了其吸收和受激发射截面。项目拟采用提拉法生长高质量Dy3+,Tb3+共掺GdScO3单晶，研究Dy3+-Tb3+离子对在GdScO3基质中共振能量传递机理，采用GaN LD泵浦，实现黄光激光高效稳定运转，从而为固体黄光激光器的发展提供工作物质。

黄光激光在生物医疗、激光钠导星、激光显示等领域具有重要应用。本项目以LD泵浦激光晶体获得黄光激光输出为研究目标，围绕Dy,Tb:GdScO3和Dy,Tb:YAG两种晶体材料，开展了以下几方面的工作：进行了高质量单晶体提拉法晶体生长工艺研究；对晶体的结构、热学和化学性能进行了表征；测试了晶体的光谱性能；设计并搭建了激光实验系统，进行了激光输出实验；分析讨论黄光激光输出的微观机理。本项目取得了较为重要的研究结果和数据，具有一定的科学意义：.1) 生长了Ф25mm×60mm高质量4%Dy3+,1%Tb3+共掺GdScO3晶体，测定了Dy3+的有效分凝系数为0.72，通过测量晶体的热学、化学等性能，优选出c向晶体进行激光实验，这些结果为提高激活离子的泵浦效率和降低晶体热效应提供了科学依据，为实现黄光激光输出和应用提供了良好基础。.2) 测定了晶体的光谱性能，计算了光谱参数，分析了掺杂离子发光的微观机理，解释了交叉弛豫、能量共振转移等对Dy3+激光运转能级的影响，与其他掺Dy晶体进行了比较，综合评估了Dy,Tb:GdScO3晶体作为黄光激光晶体的性能。这为Dy3+掺杂晶体激光系统的设计和实验方案优化改进提供了参考。.3) 在国内首次在泵浦功率为4.6W，输出镜透过率为2%的条件下获得Dy,Tb:YAG晶体的黄光激光输出，使用光纤光谱仪测得波长为582.1nm，这可进一步推动黄光晶体在生物医疗、激光钠导星、激光显示等领域的应用。