Optical polarimetric measurement of surface acoustic waves

Abstract

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 measured with an optical polarimeter. We show that the slope of the periodically tilting surface due to the coherently driven SAW is translated into the angle of polarization rotation, which can be straightforwardly calibrated when polarimeters work in the shot-noise-limited regime. The polarimetric measurement of SAWs is, thus, beneficial for quantitative studies of SAW-based technologies.