The development of dynamic holographic acoustic tweezers

Radiation forces due to sound waves can be used to create acoustic tweezers that can trap and manipulate matter without contact. They provide unique advantages when compared to the more established optical tweezers, such as higher trapping forces per unit input power and the ability to trap a wide range of sample materials. This paper describes the development of dynamically reconfigurable holographic acoustic tweezers that can independently manipulate multiple millimetre-scale particles. We present hardware and algorithms that create converging acoustic radiation forces at multiple locations in space with an array of phase controlled emitters. We experimentally demonstrate a 40 kHz airborne ultrasonic system and manipulate up to 25 particles simultaneously. As the acoustic field is dynamically up-dated in real-time and manipulation speeds of up 40 mm/s are shown. When considered on the scale of a wavelength, this system has similar manipulation capabilities to optical tweezers. We show experimental resul...