根据表面波声光效应的原理, 实验上建立了固体表面微振动的激光衍射测量系统.当激光斜入射到微振动引起的液体表面波上, 观察到了清晰、反衬度非常高的衍射图样.利用MATLAB软件对拍摄的衍射图样进行扫描, 得到了衍射光斑的光强分布图, 并根据衍射图样宽度与表面波振幅的解析关系式, 求出了液体表面波的振幅, 其大小在微米量级.改变样品池中液体的深度, 测得不同深度下液体表面波的振幅, 给出了表面波振幅与液体深度之间的解析关系, 并发现了液体对微振动的放大效应.利用液体对微振动的放大效应, 求出了固体表面微振动的振幅, 实现了固体表面微振动的探测.

According to the acousto-optic effect, a measurement system of the vibration in the solid surface was built by laser diffraction. When the laser beam illuminated obliquely to the liquid surface wave caused by the vibration, the clear and very high diffraction pattern was observed. The diffraction pattern was scanned by use of MATLAB software. The light intensity distribution of the diffraction pattern was received. Based on the analytical relationship between the diffraction pattern width and the amplitude of the surface wave, the amplitude was obtained. And its size was in microns category. When the depth of the sample pool was changed, the surface wave amplitude was given. The relationship between liquid depth and the amplitude was provided. And the amplification effect concerning the vibration of the liquid was found. Then the vibration amplitude in the solid surface was got. Therefore the micro vibration in the solid surface was achieved.