Real-time detecting and tracking nanoscale feeble vibrations based SF-AM AFM

Nanoscale vibration, a critical nanomechanical property of cell membranes/walls, is a crucial aspect of cell physiology. However, limitations of current nanoscale vibration detecting methods remain the major obstacle for scientific study and cell vibration experiments. Due to the absence of effective method of feeble nanoscale vibration detecting, most sorts of quantitative and dynamic cell vibrations cannot be observed. Therefore, a real-time tracking detection method is vital for the study of cell physiology. In this paper, a real-time tracking detection of nanoscale vibrations based on sweep frequency (SF) - amplitude modulation (AM) method using cantilever sweep frequency as a carrier frequency was proposed. Furthermore, the process of tip-sample vibration coupling is analyzed by using the idea of amplitude modulation model. The nanoscle vibration detecting experiments were carried out on a piezoceramic disc, which can mimic cell vibrations. The experiment results show that the SF-AM AFM real-time vibration tracking and detecting approach can accurately detect and track feeble sample vibration within few nanometers amplitude.