Researchers at the Max Planck Institute for Intelligent Systems have developed acoustic ‘holograms’ that can assemble matter into 3D objects using sound.
The study involved a new use for ultrasound, moving small building blocks in precise ways to assemble
3D objects.
3D printed plates were then used to produce a specific sound field, with several plates combined to
create an acoustic hologram in a specific 3D shape.
These ‘monolithic acoustic holograms’ can reconstruct diffraction-limited acoustic pressure
fields and ultrasound beams, creating holograms with reconstruction degrees of freedom two orders of magnitude higher than commercial
phased array sources.
The researchers claim that the technique is inexpensive, useful for transmission and reflection elements as well
as scaling well to higher information content, larger aperture size and higher power.
The three-dimensional pressure and phase
distributions produced by these acoustic holograms allows the researchers to demonstrate new approaches to controlled ultrasonic manipulation of
solids in water and of liquids and solids in the air.
The researchers believe that the acoustic holograms will
enable new capabilities in beam-steering and the contactless of power, improve medical imaging and drive new applications of ultrasound.