A distance regulation scheme for scanning near-field optical microscopy

In this letter we present a detection scheme for shear force distance regulation in scanning near-field optical microscopy. Instead of an optical detection of the amplitude of tip vibrations and damping due to shear forces, a piezoelectric pickup has been developed. It is shown that the signal obtained with this pick up is of comparable or even superior sensitivity than the conventional optical scheme and can be easily incorporated into every near-field microscope. Because of its easy implementation and adjust free performance, the method has the potential to considerably simplify the usage of near-field microscopes. (C) 1996 American Institute of Physics.