Chirality-tunable vortex laser through intracavity scattering asymmetry

Laguerre–Gaussian (LG)-mode lasers offer compact sources that directly emit eigen-vortex beams with high transmission stability, making them attractive for modern integrated information technologies. However, the practical development of compact vortex lasers has long been fundamentally limited by the intrinsic degeneracy between vortex beams with opposite chirality. Here, we demonstrate a versatile mechanism for tuning the helical chirality of LG-mode lasers by engineering intracavity scattering asymmetry. By inserting a nanoparticle-coated scattering plate into the cavity, we introduce differential scattering losses between vortex modes with opposite chirality. The scattering-induced asymmetry is strongly dependent on the nanoparticle distribution. Consequently, the degree of chirality can be continuously and arbitrarily tuned simply by adjusting the position of the scattering plate. Finally, we constructed a reconfigurable vortex laser with fast-switchable chirality by integrating a computer-controlled motorized translation stage with the scattering plate. The chirality can be switched on demand with a response time as short as 4 ms. This approach can be extended to arbitrary vortex lasers to achieve topological-charge-tunable and chirality-switchable vortex beam generation, representing a key step toward applications in integrated optical communications, optical tweezers, and beyond.