Abstract: A method of carrying out sub-resonant tapping in an atomic force microscope includes causing a probe that is disposed above a sample to be translated in a direction parallel to a horizontal plane defined by the sample and to oscillate in a vertical direction that is perpendicular to the horizontal plane about an equilibrium line that is separated from the horizontal plane by a vertical offset. As a result, the probe repeatedly taps a surface of the sample. Each tap begins with a first contact of the probe on the surface followed by a progressive increase in force exerted by the sample on the probe until a peak force is attained. The vertical offset is controlled by relying at least in part on a feature other than the peak force as a basis for controlling the vertical offset.

Abstract: A method of carrying out sub-resonant tapping in an atomic force microscope includes causing a probe that is disposed above a sample to be translated in a direction parallel to a horizontal plane defined by the sample and to oscillate in a vertical direction that is perpendicular to the horizontal plane about an equilibrium line that is separated from the horizontal plane by a vertical offset. As a result, the probe repeatedly taps a surface of the sample. Each tap begins with a first contact of the probe on the surface followed by a progressive increase in force exerted by the sample on the probe until a peak force is attained. The vertical offset is controlled by relying at least in part on a feature other than the peak force as a basis for controlling the vertical offset.