An analog high-speed single-cycle lock-in amplifier for next generation AFM experiments

In this paper, we present a new architecture for analog amplitude demodulation in high-speed atomic force microscopy (AFM) applications. It features single-cycle capabilities and the possibility to work with elevated cantilever resonance frequencies up to 9MHz. This latter feature is particularly important in view of the upcoming next generation of high resonance frequency cantilevers. As a proof-of-principle, we show a prototype of the proposed single-sideband upconversion architecture to be able to work with a conventional MultiMode 8 AFM system (Bruker) and a FastScan-A cantilever in air with f(res) approximate to 1.6 MHz. Overall, the presented lock-in amplifier with its improved demodulation speed will foster the research activities towards faster imaging speeds in AFM applications and thereby allow to further establish it as a tool for real-time studies of the dynamics of molecular and even atomic processes.