铒掺杂钇镓石榴石晶体生长及其3μm波段激光的能量回收效应研究

Laser is an important topic associated with the people's livelihood, and the research on practical laser materials and key scientific problems is the foundation of the lasers. The lasers at the wavelength of 3 μm are localized in the mid-infrared, and have promising applications in the medicine, biology, pollution measurement and detection, military, etc.. The research on the 3 μm laser is a hot topic in laser regimes, and this laser is urgently required to be developed. The 4I11/2→4I13/2 transition of Er3+ ions can emit the 3 μm photons and the lasing based on this transition is an important technique for the 3 μm lasers, but the long lifetime of 4I13/2 energy of Er3+ ions in bulk materials generating the self-terminating and multi-upconversion process, and the large quantum defects determining strong thermal effects constrained the development of practical gain media and laser devices. In this project, aiming at the bottleneck of 3 μm lasers, we propose to choose the novel Erbium doped yttrium gallium garnet (Er:YGG) as the 3μm laser materials, and study the growth and energy recycling effects which could conquer the intrinsic problems of Er3+ ions shown above. We will also find the key parameters for the laser performance and reveal the component-performance relationship of 3 μm laser materials. The practical devices will be designed and developed. This research including the crystal growth, theoretical research, experimental confirmation, and practical device design and applications, which constitute a full chains for the laser materials. This project will develop practical materials and devices with independent intellectual property rights for the 3μm lasers and have important scientific and practical significance.

激光在关系国计民生的各领域有重要应用需求，可实用激光材料的研制和关键科学问题的解决是激光发展的基础。波长为3μm的激光处中红外波段，在医疗、污染检测、军事对抗等领域有重要需求，是激光领域的研究热点之一且亟需发展。铒离子的4I11/2→4I13/2电子跃迁是实现3μm波段激光辐射的重要技术，但Er3+的4I13/2能级寿命过长所引起自终止效应和系列上转换过程以及量子亏损大引起的强热效应限制其发展，前期研究表明4I13/2能级电子的能量回收和利用可解决上述系列问题。本项目针对3μm波段激光的发展瓶颈，从晶体生长做起，优选铒掺杂钇镓石榴石新晶体为研究对象，通过探索关键能量回收效应解决上述难题，揭示影响激光效果的系列关键参数和晶体构效关系，发展可实用器件设计。相关研究贯穿“晶体生长-理论探索-实验验证-器件设计和应用”的全链条，发展有实用价值和自主知识产权的3μm波段激光材料和器件，有重要意义。

Er3+离子3μm 波段激光在医疗、生物工程、污染检测等领域有重要需求，同时该波段激光还是光参量振荡产生3-5μm以及8-12μm的重要泵浦波长。本项目针对Er3+离子4I13/2能级寿命过长所引起自终止效应和系列上转换过程以及量子亏损大引起的强热效应限制等关键问题，提出以铒掺杂钇镓石榴石（Er:YGG）晶体为研究对象，发展了中红外3μm波段可实用的激光晶体器件。项目从晶体生长和制备做起，克服Ga2O3挥发所引起的组分偏析和镓变价等问题，确定了最优晶体生长工艺，实现了不同掺杂组分的高质量Er:YGG晶体制备；开展了晶体结构、组分、热学与光学等基本物理性能表征，总结了不同Er3+离子掺杂浓度对其基本物理特性与能量回收效应的影响规律；结合相关激光实验对能量回收理论进行完善，实现了突破量子极限的3μm瓦级激光输出，确定最优激光晶体器件参数；此外，还基于Er:YGG晶体实现了1.6μm人眼安全波段斜效率为42.1%的瓦级连续激光输出，并利用Co:LaMgAl11O19被动光开关晶体实现了最短脉宽为2.27 µs的被动调Q脉冲激光输出。本项目的开展丰富了中红外晶体激光晶体材料与器件，对发展具有我国自主知识产权的功能材料、保持我国在激光和非线性晶体材料方面的先进性起到积极推动作用。在本项目资助下，发表学术论文15篇，授权发明专利2项，培养6名博士研究生和1名硕士研究生。