Tunable topological charge vortex microlaser with ultrafast controllability

The orbital angular momentum (OAM), both integer and fractional, carried by vortex light beams holds a great promise for forefront development of multi-dimensional high capacity spin-OAM optical communication and quantum information–processing technologies. While integrated vortex beam generators have been previously demonstrated in different optical settings, dynamical and ultrafast control of (fractional) OAM laser emission with low-power control, suitable for high-speed optical communication and computing, remains challenging. By harnessing the properties of total angular momentum conservation, spin-orbit interaction, optically controlled non-Hermitian symmetry breaking and fast transient optical gain dynamics, we demonstrate an on-chip integrated (fractional) OAM-tunable vortex microlaser, providing ultrafast reconfigurable chiral light emission with desired topological charge at a single telecom wavelength. Our work provides a route for the development of the next generation of multi-dimensional high capacity information system in both classical and quantum regimes.