Vortex Beam Lasing with Controllable Orbital Angular Momentum and Directivity from Laser-Fabricated Gear-Shaped Perovskite Microdisks.

Abstract

Orbital angular momentum (OAM) of light provides a fundamental degree of freedom for advanced photonics, yet compact, chip-scale vortex sources remain elusive. Here, we demonstrate OAM emission from optically pumped halide perovskite MAPbBr3 microdisks featuring gear-shaped sidewall modulations realized via femtosecond laser patterning. A rotating multi-beam printing procedure, assisted by a spatial light modulator, achieves sub-10 nm precision in defining the azimuthal grating geometry. The resulting gear-shaped microdisks exhibit low-threshold (50-70 μJ/cm2) vertical lasing, emitting vortex beam superpositions with geometry-controlled directionality and predefined yet opposite topological charge ±l at precisely specified wavelengths. Modeling and back-focal-plane imaging confirm the designed emission characteristics. Leveraging this unique high-precision printing strategy, we introduce a symmetry-breaking cavity with non-uniform azimuthal grating, enabling angular splitting of OAM beams carrying opposite l. This work establishes laser nanopatterning as flexible, direct route to structured-light perovskite microlasers and lays the groundwork for on-chip OAM sources with reconfigurable helicity.