Fig. 1: Schematic of a non-Hermitian controlled vortex microlaser¹⁰ and photocurrent detection of the orbital angular momentum (OAM) states of the generated vortex light¹¹.

The non-Hermitian interaction mediated by the externally applied control pump on the bus waveguide can be flexibly switched for the emission of OAM states with desirable chirality from the spin–orbit engineered microring. The vortex beam emitted on the WTe₂ photodetector induced a nonlocal photocurrent with a magnitude proportional to its quantized OAM order. Hence, the measurement of photocurrent amplitudes can directly read out the topological charges of the OAM of light