Increasing the imaging speed of tapping mode atomic force microscopy (AFM) has important practical and scientific applications. The scan speed of tapping-mode AFMs is limited by the speed of the feedback loop that maintains a constant tapping amplitude. This article seeks to illuminate these limits to scanning speed. The limits to the feedback loop are: (1) slow transient response of probe; (2) instability limitations of high-quality factor (Q) systems; (3) feedback actuator bandwidth; (4) error signal saturation; and the (5) rms-to-dc converter. The article will also suggest solutions to mitigate these limitations. These limitations can be addressed through integrating a faster feedback actuator as well as active control of the dynamics of the cantilever.
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机译:提高攻丝模式原子力显微镜(AFM)的成像速度具有重要的实际和科学应用。攻丝模式原子力显微镜的扫描速度受反馈环路速度的限制,反馈环路保持恒定的攻丝幅度。本文旨在阐明扫描速度的这些限制。反馈环路的局限性是:(1)探头的瞬态响应缓慢;(2)高质量因子(Q)体系的不稳定性限制;(3)反馈执行器带宽;(4)误差信号饱和;以及 (5) 个 RMS 至 DC 转换器。本文还将提出缓解这些限制的解决方案。这些限制可以通过集成更快的反馈执行器以及对悬臂动态的主动控制来解决。
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