PhantomFields: fast time and spatial multiplexation of acoustic fields for generation of superresolution patterns

Ultrasonic fields generated by phased arrays can be tailored to obtain a custom pattern of acoustic radiation forces. These force fields can pattern particles as well as be felt by the human hand, enabling applications for bioprinting and contactless haptic devices. The forcé fields can be switched orders of magnitude faster than the reaction time of the particles that it pushes or the human mechanoreceptors of touch. Therefore, a quick multiplexation in time or in space of different acoustic fields will be perceived as the average field. In this paper, we optimise the non-linear problem of decomposing a target force field into several multiplexed acoustic fields. We create averaged fields, PhantomFields, that cannot be created by a regular (unique) emission of an acoustic field. We improve accuracy by time multiplexation and spatial multiplexation, i.e. quick rotation of the emitters. These processes improve the resolution and strength of the obtained fields without the requirement of new hardware, opening up applications in haptic devices and 3D printing.