Visible pulsed vortex beams with controllable temporal profiles and customizable transverse modes are of great scientific and practical interest. The generation of visible pulsed vortex beams from lasers remains a significant challenge due to the limited availability of well-developed saturable absorbers (SAs) in the visible spectrum. Here, we report the generation of 640 nm passively Q-switched vortex beams from a Pr:YLF all-solid-state laser, for the first time to the best of our knowledge, using quasi-2D (PEA)₂(CsPbBr₃)_n−1PbBr₄ perovskites as the SA. Stable pulsed TEM_0,0 mode generation with a tunable pulse duration from 826.5 to 371.2 ns and a corresponding repetition rate from 63.7 to 121.3 kHz was achieved. Additionally, customizable transverse modes were generated from the Pr:YLF laser cavity using a noncollinear pumping technique to precisely manage the gain and loss characteristics of intracavity transverse modes. A first-order vortex beam at 640 nm was obtained through astigmatic mode conversion from the passively Q-switched Pr:YLF laser. These results present a new paradigm in generating visible pulsed vortex beams, offering excellent application potential in underwater communication and super-resolution imaging.

中文翻译：

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具有 （PEA）2（CsPbBr3）n−1PbBr4 钙钛矿可饱和吸收体的 Q 开关 Pr：YLF 激光器中可见脉冲涡旋光束的时空调控


具有可控时间剖面和可定制横向模式的可见脉冲涡旋光束具有重要的科学和实践意义。由于可见光谱中发达的可饱和吸收体 （SA） 的可用性有限，因此从激光器产生可见脉冲涡旋光束仍然是一个重大挑战。在这里，我们首次报告了 Pr：YLF 全固态激光器产生 640 nm 被动 Q 开关涡旋光束，这是据我们所知，使用准 2D （PEA）₂（CsPbBr₃）_n-1 PbBr₄ 钙钛矿作为 SA。实现了稳定的脉冲 TEM_0.0 模式生成，可调谐脉冲持续时间为 826.5 至 371.2 ns，相应的重复频率为 63.7 至 121.3 kHz。此外，使用非共线泵浦技术从 Pr：YLF 激光腔生成可定制的横向模式，以精确管理腔内横向模式的增益和损耗特性。通过被动 Q 开关 Pr：YLF 激光器的散模转换获得 640 nm 的一阶涡旋光束。这些结果为生成可见脉冲涡旋光束提供了一种新的范式，在水下通信和超分辨率成像中提供了极好的应用潜力。