40 years of measuring properties with atomic force microscopy.

This paper gives a short personal retrospective of some of the AFM methods developed in the Grutter group. It gives an overview of methods developed with the aim of measuring properties with high spatial and temporal resolution. Frequency mode AFM has over the past 40 years developed into a spatially resolving technique allowing spectroscopy of quantum dots and traps in semiconductors with single charge sensitivity. Properties can also be measured on ultrafast time scales by using pump-probe techniques, resolving a 100 fs short optical pulse. Two major challenges are addressed in a brief outlook: reproducible tip fabrication and open-source automatisation to increase throughput and statistics.