Fig. 3: Mechanical and optical angular momentum.
From: GHz acousto-optic angular momentum with tunable topological charge
a, b Sketch of the moving boundary coupling mechanism, relying upon the phase shift of reflected waves. c Amplitude and phase polar maps of the acoustic vortex with ℓ = 1. d Amplitude and phase polar maps of a perfectly reflected planar optical wavefront, considering a maximum acoustic displacement of λo/4. e, f Gram matrices of the mechanical and optical bases considering the range of ℓ from 1 to 3.
