Fig. 5. Holographic IDTs for customized 3D high-frequency acoustic beams.

(A and D) Schematics of two different holographic IDTs for generating 3D focused beams and acoustic vortices. With respect to the IDT design in (A), numerical simulation results of a generated focused acoustic beam at 10 MHz in (B) z = 1.2 mm and (C) y-o-z planes. With respect to the IDT design in (D), numerical simulation results of the generated acoustic vortex beam at 10 MHz are in (E) z = 1.2 mm and (F) y-o-z planes. In the simulation results (B), (C), (E), and (F), the left and right images represent the phase arg(p) and intensity |p|² of acoustic waves. The field results are obtained through finite element modeling simulations. Details of the numerical simulation setup and 3D results can be found in section S2.