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（TDL）是一种非常有前途的激光器架构，可以产生高平均功率和高能量的脉冲。由于激光介质中的晶体长度短且光束直径大，因此可以在最大程度地减少有害的非线性和热效应的同时调整功率。这一关键优势仍然存在，特别是对于产生具有高峰值功率的皮秒和飞秒脉冲。到目前为止，TDL 概念在高功率锁模振荡器方面的全部潜力尚未得到充分利用，因为大多数有关功率缩放的研究都集中在增益材料 Yb:YAG 上。由于增益带宽有限，Yb:YAG 并不是最适合生成飞秒脉冲的激光晶体。相比之下，掺镱倍半氧化物Yb:Lu2O3和Yb:LuScO3无论是单晶还是透明陶瓷，由于其宽增益带宽、低量子缺陷、强晶体场效应、优异的热机械性能和低声子能量，是非常有前途的激光介质，用于产生高能量和高平均功率的超短脉冲。因此，本项目的目的是研究实现大面积（直径>12mm）高质量Yb:Lu2O3和Yb:LuScO3晶体和陶瓷的不同关键技术及其在高功率TDL中的应用。因此，拟议的项目将包括以下研究： 将分析和克服当前热交换生长方法和边缘限定薄膜馈送生长技术在可生产晶体的尺寸和质量方面的局限性。将研究成分、局部晶体结构和光谱特性之间的关系，以开发和生产具有显着改善的激光性能的晶体。将进一步研究纳米晶粉末的湿化学合成，以获得高纯度、高烧结活性并避免团聚。采用真空烧结技术对Yb:Lu2O3和Yb:LuScO3粉末进行烧结，生产出高光学质量的陶瓷。在验证所制备的目标直径超过 12 mm 的陶瓷的光学质量后，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。在理论考虑的支持下，我们将制定适用于超快的倍半氧化物激光晶体和陶瓷的系统优化指南 薄盘激光器具有高平均功率的锁模薄盘激光器可进行系统分析，并将所生产的倍半氧化物陶瓷（大直径）与倍半氧化物晶体的性能进行比较。将使用商用 SESAM 来实现被动锁模振荡器，以研究和鉴定平均功率超过 150 W 且脉冲持续时间低于 500 fs 的增益材料。