Fig. 4: Electrically tunable vortex topological charge.
From: GHz acousto-optic angular momentum with tunable topological charge
a Phase profile around a vortex with topological charge ℓ = 1 generated by driving the BAWR at 750 MHz. Experimental data points are the blue dots, with the red lines showing their moving mean value. The upper and lower left insets show the measured and simulated phase profiles. The dashed circle in the upper left inset shows the circulation path for the determination of the phase profile. b, c Corresponding data for vortecies with ℓ = 2 and ℓ = 3 excited at 927 MHz and 1150 MHz, respectively.
