A surface acoustic wave (SAW) is utilized in diverse fields ranging from physics,
engineering, to biology for transducing, sensing, and processing various signals. Optical
measurement of the SAW provides valuable information since the amplitude and the phase
of the displacement field can be measured locally with the resolution limited by the spot size
of the optical beam. So far, optical measurement techniques rely on modulation of the optical
path, phase, or diffraction associated with SAWs. Here, we demonstrate that SAWs can be …