  Commercial atomic force microscopes usually use a four-segmented photodiode
to detect the motion of the cantilever via laser beam deflection. This read-out
technique enables to measure bending and torsion of the cantilever separately.
A slight angle between the orientation of the photodiode and the plane of the
readout beam, however, causes false signals in both readout channels, so-called
crosstalk, that may lead to misinterpretation of the acquired data. We
demonstrate this fault with images recorded in contact mode on ferroelectric
crystals and present an electronic circuit to compensate for it, thereby
enabling crosstalk-free imaging.
