无序结构Tm,Ho:CGA超快激光晶体的光谱调控和优化生长研究

近几年，全固态2μm波段超快激光的研究获得了长足进步，但仍面临着功率较低和脉宽较宽的瓶颈。其中，缺少适合LD泵浦的兼具高热导和宽光谱特性的激光晶体材料是制约2μm波段超快激光发展的重要因素。本项目以Tm,Ho:CGA晶体为研究对象，提出调控Tm/Ho双掺离子发射峰强度和调控局域结构配位环境实现光谱展宽和平滑的技术方案，揭示双掺激活离子能量传递规律，探索结构调控离子对光谱展宽和晶体热学性能的影响；并采用创新的助熔剂-提拉法，克服熔体粘度大，掺杂离子扩散不畅形成条纹包裹等难题，提高晶体的热学性质和光学均匀性，探明晶体缺陷形成抑制机理及其对晶体性能的影响规律。本项目的开展，一方面对深入理解Tm/Ho稀土离子在无序结构晶格场中的能量传递以及光谱展宽特性具有重要的科学意义；另一方面将获得高光学质量的Tm,Ho:CGA晶体结构设计方案和生长工艺，为2μm波段超快激光的发展打下坚实的材料基础。

In recent years, great progress has been made in the research of all-solid ultrafast laser near 2-micron. But there are still development bottlenecks in terms of output power and pulse width. The lack of crystal materials suitable for LD pumps with both high thermal conductivity and broad spectral properties is an important factor restricting the development of 2 μm ultrafast lasers. In this project, Tm,Ho:CGA crystals were selected as the best research object. And, technical solutions are proposed to achieve spectral broadening and smoothing by adjusting the emission intensity of Tm / Ho co-doped ions and adjusting the local structure coordination environment. Meantime, the energy transfer law of co-doped activated ions, and the influence of the extra introduced ions on spectral broadening and thermal properties will be well revealed. In addition, an innovative method called the Flux-Czochralski method will be carried out to overcome the growth striation problems, which were caucused by the large melt viscosity, low diffusion rate of the activated ions in the growth. Thus, not only the thermal properties and optical uniformity of the Tm,Ho:CGA crystals will be improved, but also the crystal defect formation inhibition mechanism and its influence on the crystal properties will be well revealed. In summary, the development of this project has important scientific significance for the deep understanding of the energy transfer and spectral broadening of Tm/Ho ions in the disordered lattice field. Moreover, both the structural design and the mature growth processes for high quality Tm, Ho: CGA crystals will also be obtained. All above will lay a solid material foundation for the development of 2 μm ultrafast laser.