Patent ID: 7856866

Claim:
A method of operating an Atomic Force Microscope (AFM) system, wherein the AFM system includes a cantilever beam attached to a base at one end thereof and a probe positioned at another end of the cantilever beam, said probe scanning across the surface of a sample under study to produce a response signal changing in accordance with a topographical profile of the sample, the method comprising the steps of: oscillating the probe at an excitation frequency in a predetermined frequency window distinct from said probe's first natural frequency; disposing said oscillating probe a separation distance from said sample under study for repetitive collisions of said probe therewith, said probe undergoing at least one grazing event between a “non-collision” state and a “collision” state thereof, wherein in said predetermined frequency window, the generated response signal undergoes grazing bifurcation, and wherein in said “collision” state, said response signal includes a characteristic frequency component; monitoring a magnitude of said characteristic frequency component of said response signal in real time; defining a reference magnitude of said characteristic frequency component corresponding to said at least one grazing event; and adjusting said separation distance between said probe and said sample to maintain the magnitude of said characteristic frequency component measured in real time substantially equal to said reference magnitude, thereby reducing impact forces between said probe and said sample during said “collision” state.