Direct measurement of the absolute value of the interaction force between the fiber probe and the sample in a scanning near-field optical microscope

Author :D. A. Lapshin, V. S. Letokhov, G. T. Shubeita, S. K. Sekatskii, and G. Dietler
Publication :Applied Physics Letters
Volume :81
Number :8
Pages :1503-1505
Year :2002

The absolute values of the force exerted by the fiber probe of a scanning near-field optical
microscope onto the surface were measured using an atomic force microscope in ambient
conditions. We demonstrate that a usually neglected static attraction force is dominant at small
dither amplitudes and is of the order of 200 nN. The tapping component of the force, often referred
to as shear force, is of the order of 1 nN at these conditions for both the tuning fork-based and
optical in resonance detection schemes. Other peculiarities of the shear force interaction are also