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.

薄盘激光器是一种非常有前途的激光器结构，可以产生高平均功率和高能量的脉冲。由于激光介质中的短晶体长度和大光束直径，功率缩放是可能的，同时最小化有害的非线性和热效应。这一关键优势尤其适用于产生具有高峰功率的皮秒和飞秒脉冲。迄今为止，由于大部分关于功率缩放的研究都集中在增益材料Yb：YAG上，所以TDL概念在高功率锁模振荡器中的全部潜力尚未得到充分利用。由于其有限的增益带宽，Yb：YAG不是最适合产生飞秒脉冲的激光晶体。相比之下，Yb掺杂的倍半氧化物Yb：Lu_2O_3和Yb：LuScO_3无论是作为单晶还是作为透明陶瓷，由于其宽的增益带宽、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，都是非常有前途的用于产生具有高能量和高平均功率的超短脉冲的激光介质。因此，本课题的目标是研究实现大面积（直径>12mm）高质量Yb：Lu_2O_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调查：将分析并克服热交换生长方法和边缘限定薄膜生长技术当前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改善激光性能的晶体，将研究成分、局部晶体结构和光谱性质之间的关系。为了获得高纯度、高烧结活性和避免团聚，将进一步研究纳米晶体粉末的湿化学合成。Yb：Lu2O3和Yb：LuScO3粉末将通过真空烧结技术进行烧结以制备高光学质量的陶瓷。对目标直径超过12 mm的所制备陶瓷的光学质量进行验证，本文将研究它们在薄片激光器中的应用和性能，并在理论的支持下，对适用于超快薄片激光器的倍半氧化物激光晶体和陶瓷进行系统的优化。锁定的高平均功率薄盘激光器进行了系统的分析和比较所产生的倍半氧化物陶瓷（大直径）的性能倍半氧化物晶体。一个被动锁模振荡器将实施与市售SESAM调查和合格的增益材料在平均功率超过150 W，脉冲持续时间低于500 fs。