A novel probe-sample separation estimation scheme for atomic force microscopy

This paper presents a novel estimation scheme to calculate the probe-sample separation in atomic force microscopy (AFM). The AFM is capable of measuring the sample topography by using a probe to interact with the sample. The interaction is dominated by the atomic force which is dependent on the probe-sample separation and sample properties. The key to successful AFM applications is accurate sensing and regulation of the probe-sample separation in nanometer scale. Our proposed scheme provides an accurate estimate of the probe-sample separation based on the information of the main sinusoidal and its harmonics. The estimation is shown to have a good performance even when noise is present.