A quartz tuning fork is an electromechanical resonator with self-actuating and self-sensing capabilities and is widely used as a force sensor in atomic force microscopy and spectroscopy. While the electrical response of a tuning fork is affected by the two prongs’ mechanical motion and stray capacitive current, a purely mechanical motion signal of the tuning fork is required for a quantitative analysis. Here, we demonstrate the extraction of a mechanical motion signal from the electrical signal of an electrically driven quartz tuning fork in various environments, including vacuum, air, and liquid. We show that the extraction formalism is well implemented in vacuum and air, but it does not work in liquid due to the largely enhanced damping and ions present in liquids. Furthermore, using the mechanical signal extracted from the electrical signal, we determine the interaction force exerted on the tip of the tuning fork in ambient air. The present extraction method enables versatile use of electrically driven tuning forks for force, mass, and environmental sensing, in which true mechanical motion signals should be used for accurate and quantitative analysis.

石英音叉是一种具有自致动和自感能力的机电谐振器，广泛用作原子力显微镜和光谱学中的力传感器。虽然音叉的电响应受两个叉的机械运动和杂散电容电流的影响，但定量分析需要音叉的纯机械运动信号。在这里，我们演示了如何在各种环境（包括真空、空气和液体）中从电动石英音叉的电信号中提取机械运动信号。我们表明提取形式可以在真空和空气中很好地实现，但由于液体中存在的阻尼和离子大大增强，因此它在液体中不起作用。此外，利用从电信号中提取的机械信号，我们确定在环境空气中施加在音叉尖端上的相互作用力。本提取方法能够将电动音叉用于力、质量和环境传感，其中应使用真实的机械运动信号进行准确和定量分析。