DIRECT MEASUREMENTS OF THE TRUE VIBRATIONAL AMPLITUDES SHEAR FORCE MICROSCOPY

A new method to measure the tip's true vibrational amplitude in the sh ear force microscopy is demonstrated. The measurements are based on mo difications of the beam diffraction method. In addition to the dither vibration, the equilibrium position of the tip is set to move along th e direction of the vibration. The ratio of ac amplitude to the derivat ive of de amplitude gives the tip's vibration. The sensitivity of this method is determined by the size of the laser focal spot times the ra tio of the ac to de signals of the diffracted light. (C) 1995 American Institute of Physics.