Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
A diagram of the element phasing and simulated focal-pressure field of a vortex beam with topological charge M = 4 (A), and transverse (B) and axial (C) slices of the simulated pressure field without focus steering and electronically steered 7 mm horizontally off the axis. The steering to the right is indicated by the white arrows. The pressure amplitude distribution is symmetric when the beam is focused on the array axis but is asymmetric when focused off the axis.
