Abstract Yttrium Aluminum Garnet (YAG) solid state laser gain media rods with an active Neodymium-doped core and an optically-clear cladding region were additively manufactured via direct-ink-writing (DIW), followed by sintering and hot isostatic pressing to form fully dense optical ceramics. Lutetium and Gadolinium were chosen as optically-inert co-doping ions in the clad to match the increase in refractive index caused by the Neodymium in the core. Either 11.6% Lutetium or 3.8% Gadolinium can be used to match the index change from 2% neodymium; however, differences in diffusion distances across the core-clad interface lead to large fluctuations in index in that region. These index fluctuations can be minimized either by matching dopants with similar diffusion distances, or by implementing a gradual gradient in the doping profile, possible through DIW, rather than a sharp compositional interface attainable via more standard fabrication methods. This improvement in index homogeneity resulted in a 40% improvement in lasing performance compared with that of a core-clad rod fabricated with a sharp interface between the doped and undoped regions.

中文翻译：

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3D 打印透明陶瓷 YAG 激光棒：匹配芯包层折射率

摘要 具有活性掺钕纤芯和光学透明包层区域的钇铝石榴石 (YAG) 固态激光增益介质棒通过直接墨水写入 (DIW) 增材制造，然后烧结和热等静压成型。致密的光学陶瓷。镥和钆被选为包层中的光学惰性共掺杂离子，以匹配纤芯中钕引起的折射率增加。可以使用 11.6% 镥或 3.8% 钆来匹配从 2% 钕开始的指数变化；然而，芯-包层界面上扩散距离的差异导致该区域的指数大幅波动。这些指数波动可以通过匹配具有相似扩散距离的掺杂剂或通过在掺杂分布中实施渐变梯度来最小化，可以通过 DIW 实现，而不是通过更标准的制造方法可以获得清晰的组成界面。与在掺杂和未掺杂区域之间具有尖锐界面的芯包层棒相比，折射率均匀性的这种改进导致激光性能提高了 40%。