Quantitative optical imaging method for surface acoustic waves using optical path modulation

A Rayleigh-type surface acoustic wave (SAW) is used in various fields as classical and quantum information carriers because of its localization, high electrical controllability, low propagation loss. Coupling hybridization between the SAW other physical systems such magnetization, electron charge, spin are recent focuses phononics spintronics. precise measurement amplitude often necessary to discuss coupling strengths. However, there only a few techniques they generally require rather complex analysis. Here we develop demonstrate straightforward technique that can quantitatively characterize SAW. The optically detects waving due coherently driven by optical path modulation. Furthermore, when system operates shot-noise-limited regime, slope displacement at spot be deduced from modulation signal. Our demonstrated will an important tool for SAW-related research.