Components For High-Speed Atomic Force Microscopy Optimized For Low Phase-Lag

Atomic force microscopy is a uniquely powerful tool for single molecule research. In addition to high-resolution imaging of static systems, recently developed high-speed atomic force microscopes (HS-AFM) enable the observation of dynamic processes at the nanoscale. HS-AFM instrumentation has been developed by systematically increasing the bandwidth of individual components. However, the phase lag and delay of those components, which are of major importance with regard to feedback stability, are often overlooked. Here, we show a high-speed atomic force microscope which takes the delay of components into account and tries to minimize them. The system consists of a small cantilever head with photothermal cantilever drive, a detection bandwidth of above 22 MHz and detector noise below 25 fm/Hz(0.5). a flexure based high-speed scanner with 1.6 mu m x 1.6 mu m lateral scan range together with a novel low phase-lag high voltage amplifier which is controlled by a custom built scan engine. The microscope, built specifically for nanobiology, is designed for robustness and optimized for measurements in liquid. The system achieves over 10 frames per second at 2000 lines per second without active resonance dampening.