Study of optical force-induced elastic wave on macroscopic mirror

The optical force-induced elastic wave is one of the fundamental mechanisms of the optical force-induced motion on a macroscopic scale, its amplitude is extremely small and easily affected by the thermal effect, limiting the development of related research and applications. This study proposes a decoupling method and its technical path for the optical force- and thermal effect-induced coupling elastic wave based on the frequency analysis of an analytical model of coupling elastic waves. The decoupling method can effectively identify the optical force-induced elastic wave. A multipulse enhancement of the amplitude of optical force-induced elastic waves is also theoretically proven based on the time domain analysis of the analytical model. To verify the method, a measurement platform is built for coupling elastic waves. The experimental results show that as the single pulse energy increases, the amplitude of the coupling elastic waves experiences nonlinear growth, which is mainly caused by the thermal effect. At a single pulse energy of 3.8 mJ, the average amplitude of the coupling elastic waves is 1.02 nm, consistent with the theoretical value of thermoelastic waves of 1.14 nm. By extracting high-frequency vibration, optical force-induced elastic waves are successfully decoupled, with the amplitude increasing linearly with the single pulse energy. At a single pulse energy of 3.8 mJ, the average amplitude is 294.9 pm, showing an enhancement compared to the theoretical value. The significance of this study lies filling a gap in the existing theoretical framework and has significant value in the application of optical force on a macroscopic scale.