Reconfigurable ultrasonic media for spatio-temporal wavefront shaping

We introduce a multiple purpose experimental platform for ultrasonic wave manipulation. It allows us to rapidly adjust the Young's modulus and the attenuation level of a medium (a shape memory polymer foil) over arbitrary two-dimensional shapes by local heating using a digitally controlled laser beam. Experiments show reconfigurable focusing, divergence, and collimation of ultrasounds generated by short laser pulses and detected by a scanning laser vibrometer. Such improved control of the propagation properties opens new possibilities for controlling high-frequency ultrasounds in a wide range of scenarios, from wave-front shaping to time-dependent wave platforms.