Tunable topological charge vortex microlaser

Optical vortices on demand Light has several degrees of freedom (wavelength, polarization, pulse length, and so on) that can be used to encode information. A light beam or pulse can also be structured to have the property of orbital angular momentum, becoming a vortex. Because the winding number of the vortex can be arbitrary, the channel capacity can be expanded considerably. Zhang et al. and Ji et al. developed nanophotonic-based methods for generating and electrically detecting light with arbitrary orbital angular momentum, a goal that has remained an outstanding challenge so far (see the Perspective by Ge). The nanophotonic platform provides a route for developing high-capacity optical chips. Science, this issue p. 760, p. 763; see also p. 707 Nanophotonic devices generate and electrically detect optical vortices carrying arbitrary optical angular momentum. The orbital angular momentum (OAM) intrinsically carried by vortex light beams holds a promise for multidimensional high-capacity data multiplexing, meeting the ever-increasing demands for information. Development of a dynamically tunable OAM light source is a critical step in the realization of OAM modulation and multiplexing. By harnessing the properties of total momentum conservation, spin-orbit interaction, and optical non-Hermitian symmetry breaking, we demonstrate an OAM-tunable vortex microlaser, providing chiral light states of variable topological charges at a single telecommunication wavelength. The scheme of the non–Hermitian-controlled chiral light emission at room temperature can be further scaled up for simultaneous multivortex emissions in a flexible manner. Our work provides a route for the development of the next generation of multidimensional OAM-spin-wavelength division multiplexing technology.