掺杂浓度三维梯度分布透明陶瓷的热场设计与制备及其激光性能调控研究

Transparent ceramics as a new type of laser gain medium play an important role in promoting the development of new lasers, but the pumping induced thermal effect severely restricts the performance of laser output. Currently, most of researchers focus on the study of multi-segment transparent ceramics along one-dimensional direction, which, however, still suffer from the problem of thermal effect. In this project, a design scheme of three-dimensional (3D) concentration gradient distribution of various doping ions is proposed based on Re:Lu2O3 sesquioxide transparent ceramics, and it is expected to effectively solve the difficulty of thermal effect. The research content of this project mainly includes the following aspects: Firstly, the reasonable concentration gradient structure of various doping ions along 3D direction is determined based on the numerical simulation results. Then, 3D printing Direct-Ink-Writing (DIW) process with double feed system is mainly studied and combined with high temperature sintering technology to prepare composite transparent ceramics. Next, in-depth analysis is carried out on the relationship between the thermal diffusion behavior of doping ions and their concentration gradient structure, and the effect of temperature distribution of transparent ceramic is further investigated on the laser performance. Lastly, high-efficiency CW laser output is studied based on the prepared transparent ceramics as laser gain medium. The preliminary research results show that the design scheme is feasible. This project will significantly improve the output laser performance via effectively avoiding the thermal effect of transparent ceramics, and it will provide reliable material and technical support for the development of high-efficiency and high-power ceramic lasers.

透明陶瓷作为激光增益介质对推动新型激光器的发展发挥重要作用，但是泵浦产生的热效应严重制约其输出激光的质量。目前普遍采用多段透明陶瓷作为激光介质的方法仍难以有效突破这一瓶颈。本项目拟以Re:Lu2O3倍半氧化物透明陶瓷为例，提出掺杂离子沿三维方向浓度梯度分布的设计方案，可望有效解决热效应难题。项目研究思路包括：首先基于数值模拟结果确定各种掺杂离子沿三维方向合理的浓度梯度；其次利用改进的具有双进料系统的3D打印浆料直写成型工艺，并结合高温烧结等技术制备复合透明陶瓷；然后深入分析掺杂离子热扩散行为与其浓度梯度结构之间的关系，以及透明陶瓷的热效应对激光性能的影响；最后以掺杂浓度三维梯度分布的透明陶瓷作为激光增益介质研究其高效连续激光输出。初步的研究结果表明研究方案可行。本项目研究将显著改善透明陶瓷中热效应对输出激光性能的影响，为实现高效高功率陶瓷激光器提供可靠的材料与技术支撑。

透明陶瓷作为一种新型光学材料，被认为可取代单晶和玻璃成为新一代固体激光材料，然而单一结构及其较低散热性能严重限制了其在高功率激光领域的应用。鉴于此，本项目采用3D打印浆料直写(DIW)成型结合高温真空烧结技术，着重开展了掺杂离子浓度梯度复合透明陶瓷的制备及其相关性能研究，主要研究内容包括：1）3D打印用透明陶瓷膏体的研究；2）基于所制备的陶瓷膏体开展了3D打印浆料直写成型工艺的研究；3）透明陶瓷的烧结理论及其制备工艺研究；4）透明陶瓷的结构与显微形貌及其热分布特性研究；5）掺杂透明陶瓷的光物理与激光性能研究。基于以上研究内容，我们取得了重要成果和关键数据包括：1）采用全溶液燃烧合成工艺，首次开展了高纯度、超精细、窄分布透明陶瓷原料粉体的制备工作，获得的粉体平均颗粒大小约为500 nm，粒径分布在200-800 nm，纯度可高达>99.99%；2）基于所制备的HPMC水凝胶以及陶瓷前驱体粉体，成功研制出适用于3D打印DIW成型用陶瓷膏体；3) 自制具有双进料系统的3D打印浆料成型系统，并基于所制备的陶瓷膏体成功打印出不同规格的陶瓷坯体，进一步以高温真空烧结工艺为基础成功制备出浓度梯度型透明陶瓷；4）研究了不同烧结温度和掺杂浓度对陶瓷晶相结构的影响，深入分析了陶瓷显微形貌、致密度与烧结温度之间的关系，确立了最佳陶瓷烧结温度工艺；5）通过测试共掺杂透明陶瓷发光谱并结合理论计算，揭示了材料内部光声子耦合物理机制；6）采用LD泵浦复合透明陶瓷实现了效率高达69%的连续激光输出。通过开展本项目研究，我们不仅成功掌握了3D打印DIW成型制备透明陶瓷坯体的新型工艺路线，而且基于该成型工艺实现了浓度梯度型透明陶瓷的复合结构。最后，通过对掺杂透明陶瓷的发光与激光性能研究，并结合陶瓷内部热分布理论模拟计算，我们深刻揭示了透明陶瓷内部复杂的粒子耦合过程，可为后续透明陶瓷的进一步应用奠定扎实的研究基础。