On contribution and detection of higher eigenmodes during dynamic atomic force microscopy

Dynamic mode operation of Atomic Force Microscopes relies on demodulation schemes to get information from different flexure modes of the cantilever while imaging a sample. In the article, we demonstrate that the conventional approach of discerning higher mode participation via amplitude and phase demodulation is not suitable for high bandwidth applications. Furthermore, we provide a method where the higher mode participation is reconstructed with high fidelity, and present a scheme for high bandwidth detection of higher modes when their participation becomes significant. These methods are shown to outperform the traditional amplitude-phase demodulation schemes in terms of speed, resolution, and fidelity. The framework developed is tested on simulations and the method's utility for first two modes is demonstrated experimentally.