In this work, we demonstrated, for the first time to the best of our knowledge, high-order vortex beams at 604 nm that were directly emitted from a Pr:YLF crystal laser. By combining a blue-diode-pumped v-type cavity for controllable Gouy phase introduction and off-axis crystal rotation for high-order HG modes generation, topological charged 604-nm vortex lasers were attained up to the third order. Furthermore, the vortex beams were found to be lasing at 604 nm that was often deemed less prone to lase compared with 607-nm in the same energy manifold. By a detailed spectroscopic study and rate equation analysis, we proposed and confirmed that the 604-nm transition of Pr:YLF crystal could be favorable in the vortex beam generation by a cavity-loss-induced gain switching process, in which the net gain at 604-nm could surpass that of 607-nm as the cavity loss was amassed beyond a threshold value.

在这项工作中，我们首次据我们所知，首次展示了从Pr：YLF晶体激光器直接发射的604 nm高阶涡旋光束。通过组合用于可控制的Gouy相引入的蓝光二极管泵浦的v型腔和用于高阶HG模式生成的离轴晶体旋转，可以得到拓扑电荷为604 nm的三阶涡旋激光器。此外，发现在相同的能量歧管中，与607 nm相比，涡旋光束在604 nm处发射激光，通常被认为不易发射激光。通过详细的光谱研究和速率方程分析，我们提出并确认Pr：YLF晶体的604 nm跃迁可能有利于通过腔损耗引起的增益切换过程产生的涡旋光束，