Acoustic manipulation of micro objects using an ultrasonic standing wave

Manipulation of micro objects in a fluid without contact has been studied experimentally using action of acoustic radiation pressure of ultrasound. It is shown that ultrasonic standing wave field of 1.75 MHz traps alumina particles of 16 μm in diameter every half wavelength. Resonance of the standing wave is not a strict condition for trapping and agglomeration of particles. Slight change in distance of the sound field or frequency brings lateral shift of trapped particles. Using two sets of standing wave field crossing to each other, the shape of agglomeration is varied. Applying focused acoustic radiation pressure of traveling wave, a limited part of trapped particles is transported