单掺Ho:SYSO混晶的生长及其2微米激光性能研究

The 2μm lasers have various and very important applications in the fields of ground-surface environment monitoring, atmospheric wind field measurement, laser remote sensing, laser medicice and optpelectronic countermeasure. At present, the 2μm laser output performance development and improvement are limited by the strong thermal effect and weak mechanical strength. This project first put forward a new high field coupling single doped Ho:SYSO mixed crystal, which possess advantages of weak thermal effect and strong mechanical strength, to resolve the problem that the high pumping strengh and weak thermal effect can not coexist in tranditional crystal. Moreover, with the characteristics of large ground state energy level splitting, wide absorbtion and emission spectrum and high thermal conductivity, the Ho:SYSO mixed crystal can achieve low pump threshold, high efficiency and wide tunable spectra 2μm laser. We intend to optimally design the crystal composition and structure and accomplish 2μm region laser gain curve with wide band. We establish 2μm laser theoretical model with Ho:SYSO mixed crystal by studying luminescence kinetics and spectral properties of Ho ion in crystal. The terminal aim is to achieve tunable, continuous wave and pulsed Ho laser. The research results of this project will obtain 2μm Ho:SYSO solid-state laser with intellectual property. These research results will promote the development of relative technique field.

2微米激光在地表环境监测、大气风场测量、激光遥感、激光医疗和光电对抗等领域都有非常重要而广阔的应用前景。目前的2微米固体激光材料存在热效应严重或机械强度不高等缺点，限制了2微米激光性能的拓展和提升。本课题首次提出一种新型强场耦合单掺Ho:SYSO混晶，该晶体同时具有热效应弱和机械强度高的优点，解决传统晶体无法兼顾高泵浦强度和弱热效应问题。此外，该晶体还具有基态能级劈裂大、吸收和发射谱宽、热导率高的特点，有利于获得低阈值、高效率和宽调谐的2微米激光输出。课题拟通过优化设计晶体组成结构，在2微米波段形成宽谱带增益曲线；通过研究Ho离子在Ho:SYSO混晶中的发光动力学行为和光谱特征，建立Ho:SYSO混晶2微米激光运转的理论模型；最终实现Ho:SYSO混晶的可调谐、连续波和脉冲激光输出，本项目的研究成果将获得具有知识产权的2微米波段Ho:SYSO混晶和固体激光器，并促进相关技术领域向前发展。

2微米激光在地表环境监测、大气风场测量、激光遥感、激光医疗和光电对抗等领域都有非常重要而广阔的应用前景。目前的2微米固体激光材料存在热效应严重或机械强度不高等缺点，限制了2微米激光性能的拓展和提升。本课题首次提出一种新型强场耦合单掺Ho:SYSO混晶，该晶体同时具有热效应弱和机械强度高的优点，解决传统晶体无法兼顾高泵浦强度和弱热效应问题。此外，该晶体还具有基态能级劈裂大、吸收和发射谱宽、热导率高的特点，有利于获得低阈值、高效率和宽调谐的2微米激光输出。本课题在国际上首次开展了Ho:SYSO混晶的生长、光谱特性和激光性能研究，采用提拉法生长了95mm长度的晶体毛坯，基于光谱特性分析和准二能级速率方程理论，预估了Ho:SYSO混晶的2微米激光性能。连续波模式下，二极管泵浦的Ho:SYSO激光器实现了最高20.7 W的2097.9 nm激光输出，相应线宽为3.1nm。重复频率20 kHz时，获得了19.6 W平均功率的声光调Q激光输出。5 kHz重复频率时，实现了20 ns的最小脉冲宽度。