Off-resonance AFM imaging mode with photothermal excitation for topography and beyond

Session

Poster Session Two

Authors

Dr Héctor Corte-León (2), Dr Pieter van Schendel (1), Mr Hans Gunstheimer (1), Dr Dominik Ziegler (1), Dr Gotthol9d Fläschner (1), Dr Christian Bippes (1), Dr Patrick Frederix (1)

Affiliations

1. Nanosurf GmbH
2. Nanosurf UK Ltd

Keywords

AFM; nanometer; Wavemode; in-liquid; cell; 

Abstract text

In this contribution, we analyse the performance of a new atomic force microscopy imaging mode called WaveMode, which is an off-resonance imaging mode that takes advantage of photothermal excitation. 

Atomic force microscopy imaging is very versatile, because it can operate in many different conditions (e.g. ambient, in-liquid, vacuum) and on many different kinds of samples, from very soft (e.g. mammalian cells), to very stiff (e.g. silicon). Although initially developed for high resolution imaging well below the optical diffraction limit, it has also developed capability to perform additional functions, such as mechanical analysis and nanolithography of the surface being studied. Towards this aim, there is a need for AFM imaging modes that combine easy, fast and robust operation, along with the ability to acquire additional sample information beyond topography. 

Here we present a relatively new imaging mode in AFM, operating at off-resonance frequencies in combination with photothermal excitation.  Off resonance imaging is relatively easy to setup and operate, combining the reduced lateral friction of on-resonance dynamic modes with the robust operation of static mode. Traditionally, off-resonance imaging modes have operated only very slowly. However, by direct photothermal excitation of the cantilever, tapping rates in the tens of kilohertz can be reached, overcoming the main speed limit of piezo excitation in conventional off-resonance modes. 

In this contribution we will discuss the technological basis for WaveMode imaging along with several examples of WaveMode imaging in air and liquid. In addition, new developments towards applications beyond topography imaging will be shown. 

References

[1] Jonathan D. Adams, Patrick L. T. M. Frederix, and Christian A. Bippes, "Breakthrough instruments and products: DriveAFM for high-performance atomic force microscopy", Review of Scientific Instruments 92, 129503 (2021) https://doi.org/10.1063/5.0081190

[2] Jonathan D. Adams, Adrian Nievergelt, Blake W. Erickson, Chen Yang, Maja Dukic, and Georg E. Fantner, "High-speed imaging upgrade for a standard sample scanning atomic force microscope using small cantilevers", Review of Scientific Instruments 85, 093702 (2014) https://doi.org/10.1063/1.4895460 

[3] Glenn C. Ratcliff, Dorothy A. Erie,Richard Superfine, "Photothermal modulation for oscillating mode atomic force microscopy in solution", Appl. Phys. Lett. 72, 1911-1913 (1998) https://doi.org/10.1063/1.121224