Crosstalk Correction in Atomic Force Microscopy

TL;DR

This paper addresses the issue of crosstalk in atomic force microscopy caused by misalignment of the photodiode, and introduces an electronic circuit to correct it, improving imaging accuracy.

Contribution

It presents a novel electronic circuit for crosstalk correction in AFM, enhancing the reliability of cantilever motion measurements.

Findings

Crosstalk causes false signals in AFM measurements.

The proposed circuit effectively reduces crosstalk in imaging.

Improved imaging accuracy demonstrated on ferroelectric crystals.

Abstract

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.