Spatial–Temporal Manipulations of Visible Pulsed Vortex Beams in a Q-Switched Pr:YLF Laser with a (PEA)₂(CsPbBr₃)_<i>n</i>−1PbBr₄ Perovskite Saturable Absorber

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 TEM0,0 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.