Adaptive Drive as a Control Strategy for Fast Scanning in Dynamic Mode Atomic Force Microscopy.

Atomic Force Microscopy (AFM) is an advanced imaging technique which features nanoscale resolution and the ability to work under physiological conditions on soft samples. Modern AFM systems offer easy access to Dynamic Mode imaging which reduces the tip-sample interaction and increases the effective resolution. However, the intrinsic nature of this driving strategy induces a trade-off between three different aspects: the scanning speed, an accurate topography reconstruction and weak interaction forces. The impact of this inherent trade-off is especially evident when imaging samples with steep and deep valleys, and artifacts are often created in the reconstructed topography. This phenomenon, known as parachuting, rapidly worsens at faster speeds. In this paper, a new strategy is proposed for limiting parachuting artifacts, based on an adaptive driving strategy, which can be easily implemented as an add-on to commercial AFM systems. The suggested method has been tested on grid samples, and it enhances the nano-imaging quality by effectively reducing artifacts in the topography.