Abstract In this work, a 1. 9 μ m Tm:YLF high-order vortex laser output is realized for the first time based on LD off-axis pumping technology. By adjusting the off-axis displacement of the output coupling mirror accurately, the maximum topological charge up to m = 20 for stable Hermite–Gaussian (HG m,0 ) mode is achieved. The conversion of high-order HG m,0 to Laguerre–Gauss (LG m,0 ) modes are further realized by a π /2 mode converter, and the topological charge and chirality of LG m,0 modes are measured by the Mach–Zehnder (MZ) interferometer system. The maximum output power of the LG 1,0 mode vortex laser was measured to be 8.5W with the central wavelength of 1908.8 nm. The wavelength and the power instability are less than 0.72 nm and better than ± 5.9%, respectively. This work proves that the 1. 9 μ m Tm:YLF laser has the potential to achieve continuous tuning and easy chirality control for the high-order vortex optical mode output, and lays a foundation for high-power mid-infrared vortex laser applications.

中文翻译：

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1.9μm Tm：基于LD离轴泵浦的YLF外腔模转换涡旋激光器

摘要 本工作首次基于LD离轴泵浦技术实现了1. 9 μ m Tm:YLF高阶涡旋激光输出。通过精确调整输出耦合镜的离轴位移，实现了稳定 Hermite-Gaussian (HG m,0 ) 模式的最大拓扑电荷 m = 20。高阶 HG m,0 到 Laguerre-Gauss (LG m,0 ) 模式的转换通过 π /2 模式转换器进一步实现，LG m,0 模式的拓扑电荷和手性由 Mach– 测量Zehnder (MZ) 干涉仪系统。LG 1,0 模式涡旋激光器的最大输出功率经测量为 8.5W，中心波长为 1908.8 nm。波长和功率不稳定性分别小于 0.72 nm 和优于 ± 5.9%。这项工作证明了 1. 9 μ m Tm：