One-channel time reversal of elastic waves in a chaotic 2D-silicon cavity

Acoustic time-reversal experiments usually need large arrays of transducers. It is shown that in a reflecting cavity with negligible absorption one is able to perform a time reversal of elastic waves using a single element. The field is measured at one point over a long period of time and the time-reversed signal is reinjected at the same position. Numerical simulations illustrate the process. Experiments carried out in silicon wafers show that it is possible to obtain an excellent temporal and spatial focusing quality.