Mechatronic Demodulation for Dynamic Atomic Force Microscopy Measurement Modes

Abstract

This paper presents the application of a mechatronic lock-in amplifier for demodulation of cantilever oscillations in dynamic Atomic Force Microscopy (AFM) measurement modes. The method is implemented using self-sensing AFM cantilevers with integrated piezoresistive deflection sensors, which are configured in AC bridge circuits for direct demodulation at the bridge circuit output. Dynamic AFM topography and phase measurements are carried out and the imaging performance is analysed. Comparison to demodulation by a conventional digital lock-in amplifier shows that the mechatronic demodulation method enables AFM imaging with significantly reduced sampling frequency without loss of imaging performance.