a, b, The electrically tunable synthetic magnetic field allows Rabi transition between different oscillatory modes: a, V = ±50 V (trajectories in blue and purple); b, V = ±200 V (trajectories in blue and purple). c, The spinor moves slowly from point A to its initial position by gradually sweeping the voltage from 0 to 1000 V, see blue curve; while altering the voltage sign producing a symmetric trajectory (purple line). d, The same as described in c but in a different case of beam width. e, f, The emitted topological charge as a function of voltage after a coupling length z =30 mm, in two different cases of beam widths. Credit: Guohua Liu, Xiliang Zhang, Xin Zhang, Yanwen Hu, Zhen Li, Zhenqiang Chen, and Shenhe Fu