Enhancing the quality of amplitude patterns using time-multiplexed virtual acoustic fields

Ultrasonic fields can push and levitate particles, heat up materials, induce contactless tactile stimuli, or affect the blood-brain barrier. Current phased-arrays can create dynamic amplitude patterns, but their quality may be insufficient due to the limited density of emitters. On the other hand, passive modulators can provide high quality, but only static patterns can be generated. Here, we show and evaluate how the average of multiple time-multiplexed amplitude fields improves the resolution of the obtained patterns when compared with the traditional single-emission method. We optimize the non-linear problem of decomposing a target amplitude field into multiple fields considering the limitations of the phased-array. The presented technique improves the quality for existing setups without modifying the equipment, having the potential to improve bio-printing, haptic devices, or ultrasonic medical treatments.