Fig. 7: Enhanced acoustic vortex energy and rotation information detection based on the rotating disk.
From: Tunable acoustic vortex generation by a compact rotating disk
a Using a roughened disk generates acoustic vortices with higher energy and higher order (Ω = 417.8 rad/s). Experimental amplitude-frequency spectrum of the roughened disk (red line), amplitude peaks of the plain disk at Ω/2π, 2Ω/2π, 3Ω/2π, 4Ω/2π, and 5Ω/2π Hz (blue point). Rotation noise amplitude spectrum of the motor without driving the disk (green line). The insets display the phase distributions for l = 4 and 5 generated by the roughened disk at frequencies of 4Ω/2π Hz and 5Ω/2π Hz, respectively. The experimental spectrum was tested at locations (z = 40 mm and R = 40 mm). b Detection of rotating information using acoustic vortex amplitude enhancement effect. Values of fworking were measured for different rotation rates and values of l, shown as square points, and were compared to the values predicted from Eq. 7, shown as solid lines. The color represents the values of l from −3 to +3.
