Atomic force microscopy using voice coil actuators for vibration isolation

This paper presents a vibration isolation system integrated with the internal actuators of an atomic force microscope (AFM) to vertically move the probe. For the motion, voice coil actuators (Lorentz actuators) are guided by low-stiffness flexures. Due to the low stiffness, the vibrations from the floor to the probe are decoupled at high frequencies. To reject the residual vibrations, the AFM probe tracks the AFM sample by using a displacement sensor. By mechanical and control design specifically for Lorentz actuators, the vertical motion has a control bandwidth that is 24 times higher than the first mechanical resonance to reject vibrations. As a demonstration of the vibration isolation performance, pits and tracks of a CD-ROM are successfully imaged without an external vibration isolator.