Fabrication of sesquioxide (Yb:Lu2O3 and Yb:LuScO3) laser materials and their applications in high power ultrafast Thin-disk lasERs (“LuThER”)

三氧化物（Yb:Lu2O3 和 Yb:LuScO3）激光材料的制备及其在高功率超快薄盘激光器（“LuThER”）中的应用

• 批准号: 410806665
• 负责人: Professor Dr. Thomas Graf
• 金额: --
• 依托单位: Institut für Strahlwerkzeuge (IFSW)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410806665?language=en
• 关键词: Fabrication; sesquioxide; Yb; Lu2O3; LuScO3

The thin-disk laser (TDL) is a highly promising laser architecture to generate pulses at high aver-age powers and high energies. Due to the short crystal length and large beam diameters in the laser medium, power scaling is possible while minimizing the detrimental nonlinear and thermal effects. This key advantage holds, especially for the generation of picosecond and femtosecond pulses with high peak powers. So far the full potential of the TDL concept for high-power mode-locked oscillators was not yet exploited as most of the investigations on power scaling were fo-cused on the gain material Yb:YAG. Due to its limited gain bandwidth Yb:YAG is not the most suitable laser crystal for the generation of femtosecond pulses. In contrast, the Yb-doped sesqui-oxides Yb:Lu2O3 and Yb:LuScO3 either as single crystals or as transparent ceramics are very promising laser media for the generation of ultrashort pulses with high energies and at high aver-age powers thanks to their broad gain bandwidth, low quantum defect, strong crystal field effects, excellent thermo-mechanical properties and low phonon energies. Therefore the aim of the present project is the investigation of the different key technologies for the realization of large-area (diameter>12mm) high-quality Yb:Lu2O3 and Yb:LuScO3 crystals and ceramics and their application in high-power TDL. The proposed project therefore will include the following investigations: The current limitations of the heat-exchange growth method and the edge-defined film-fed growth technique concerning size and quality of the producible crystals will be analyzed and overcome. The relation between the constituents, the local crystal structure, and the spectral properties will be investigated in order to develop and produce crystals with significantly improved laser perfor-mance.The wet chemistry synthesis of nano-crystalline powders will be further investigated to obtain high purity, high sintering activity and avoid agglomeration. The Yb:Lu2O3 and Yb:LuScO3 powders will be sintered by the vacuum sintering technology to produce ceramics with high optical quality. Up-on validation of the optical quality of the prepared ceramics with targeted diameters exceeding 12 mm, their application and performance in thin-disk lasers will be investigated.The developed sesquioxide crystals and ceramics will be implemented in cw anSupported by theoretical considerations we will elaborate a guideline for the systematic optimiza-tion of sesquioxide laser crystals and ceramics that are suited for ultrafast thin-disk lasersd mode-locked thin-disk lasers with high average powers to perform a systematic analysis and compare the per-formances of the produces sesquioxides ceramics (with large diameters) to that of the sesquiox-ide crystals. A passively modelocked oscillator will be implemented with commercially available SESAMs to investigate and qualify the gain materials at average powers beyond 150 W and at pulse duration below 500 fs.

薄片激光器(TDL)是一种非常有前途的高平均功率、高能量的激光结构。由于激光介质具有较短的晶体长度和较大的光束直径，因此可以进行功率调节，同时将有害的非线性和热效应降至最低。这一关键优势仍然存在，特别是对于具有高峰值功率的皮秒和飞秒脉冲的产生。到目前为止，TDL概念在高功率锁模振荡器中的潜力还没有得到充分的开发，因为大多数关于功率缩放的研究都集中在Yb：YAG增益材料上。由于Yb：YAG的增益带宽有限，并不是最适合产生飞秒脉冲的激光晶体。相比之下，掺Yb的倍半氧化物Yb：Lu_2O_3和Yb：LuScO_3无论是作为单晶还是作为透明陶瓷，都是非常有希望产生高能量、高平均功率的超短脉冲的激光介质，因为它们具有宽的增益带宽、低的量子缺陷、强的晶场效应、优异的热机械性能和低的声子能量。因此，本课题的目的是研究实现大面积(直径12 mm)高质量Yb：Lu2O_3和Yb：LuScO_3晶体和陶瓷的不同关键技术及其在大功率TDL中的应用。因此，拟议的项目将包括以下研究：将分析和克服目前热交换法和边缘限定薄膜生长技术在可生产晶体的尺寸和质量方面的局限性。为了开发和生产具有显著提高激光性能的晶体，将研究其成分、局部晶体结构和光谱性质之间的关系。将进一步研究湿法化学合成纳米晶粉末，以获得高纯度、高烧结活性和避免团聚。采用真空烧结技术对Yb：Lu2O3和Yb：LuScO_3粉末进行烧结，制备出高光学质量的陶瓷。在对所制备的直径超过12 mm的陶瓷的光学质量进行验证的基础上，我们将研究它们在薄盘激光器中的应用和性能。所开发的倍半氧化物晶体和陶瓷将在连续波中实现，并从理论上支持，我们将阐述适合于超快薄盘激光器的倍半氧化物激光晶体和陶瓷的系统优化指南，以进行系统的分析和比较所制备的倍半氧化物陶瓷(大直径)和倍半氧化物晶体的性能。被动锁模振荡器将用商业上可用的SESAM实现，以研究和鉴定平均功率超过150W，脉冲宽度低于500fs的增益材料。