Theoretical and visualization study of laserinduced surface acoustic wave on annular stator

Abstract

The mechanism of laser-induced surface acoustic wave (SAW) on annular stator is theoretically and experimentally studied. An annular stator with groove arrays is specifically designed. The physical model of laser-induced SAW on the stator is established, and the key factors influencing the wave amplitude are disclosed. We introduce a new kind of visualization method to detect laser-induced SAW on the copper-made annular stator, under a pulsed laser of 1053 nm wavelength, 30 ns pulse width and 1 mJ pulse energy. The results show that when the location of the irradiating laser spot is near the groove arrays, the SAW propagating towards the groove will be attenuated and absorbed immediately by the groove arrays, while the SAW away from the groove can keep propagating along the stator surface. In this way, the one-way propagation of laser-induced SAW is successfully acquired. In the contrast experiments, the laser-induced SAW travels in both directions on a copper ring without groove arrays, resulting in a chaotic state of the surface acoustic wave. The one-way SAW induced by pulsed laser on the annular stator will be used in the laser-driven SAW motor in the future.