A new paradigm to drive NC-AFM towards fast imaging

Non-contact atomic force microscopy (NC-AFM) is the highest-resolution imaging technique that exists today. Like every imaging approach, it is bound by a speed-spatial resolution trade off: in general, a precise detection takes time, and a fast detection is noisy. In particular, the force detection (implicitly in Hz) is done by a probe driven at resonance, which must oscillate "cleanly" (ie. have a high quality factor) to have a high spectral, and hence spatial resolution. This implies that the probe takes a long time to reach equilibrium, when passing from one pixel to the next. Let ? be of the time to detect a pixel (ms), and ?F be the implicit force error (Hz), then a figure of merit of the detection is 1/(??F). It is a hard upper boundary on the types of experiments possible, and a hard lower boundary on their cost.

With current instruments based on PLL, this figure is approximately 1/(??F) = 0.3. Our novel paradigm, with a very different approach to stimulus and detection, is based on the ESE protocol, achieving super-fast equilibration. We radically improve the possibilities of NC-AFM, achieving a figure of at least 1/(??F) = 1.9. In other words, we offer a six-fold improvement to the state of the art.