Experiments of wave cancellation with elastic phononic crystal

The objective of this work is to experimentally demonstrate that two incident beams of ultrasonic waves can be cancelled by using an elastic phononic crystal (PC) prism. Although PCs are known to be used for wave cancellation, there appears no experimental demonstration especially for elastic waves. Here, we use an elastic PC prism embedded in an aluminum plate, which can split an input incident beam into multiple output beams. Two signals of different incident angles are reversely sent to the prism for the wave cancellation experiment. For successful wave cancellation experiments, the magnitudes and phase difference of the input sources were carefully tuned. The experimental results were found to agree well with the predictions from numerical simulations.