Liquid channel tunable lens for phased-based ultrasonic beamforming

This work reports on the design and characterization of a tunable lens with a planar aperture that employs liquid channels to perform phase-based beamforming. The desired phase patterns are produced using specific speed-of-sound profiles and can be flexibly configured for a range of frequencies and beam types without changes to its shape or structure. Measurements of the fields show that the lens performs comparably to stepped designs, such as the fraxicon, for a range of focal configurations. The planar geometry and reconfigurable phasing provide for a range of possible applications from nearfield trapping to imaging and therapeutics.