Observation of the Talbot effect from a surface-acoustic-wave dynamic grating

We demonstrate the dynamical Talbot effect caused by optical diffraction from standing surface acoustic waves (SAWs). The Talbot effect is a wave interference phenomenon in the Fresnel regime, and we observe it with a fiber-based scanning optical interferometer on a SAW Fabry-Perot cavity. By studying the interferometric signal at 1 GHz, next to the usual phase term we discover the existence of an amplitude-modulated term which vanishes at periodic positions when we displace the acoustic device relative to the beam focus. With this, we reveal the optical Talbot effect where, despite the curved wavefronts of the optical field, the conventional Talbot length appears. Finally, we propose to use the amplitude modulation as a different way of imaging surface acoustic waves.