Ultrafast nanoscopy

Innovation in science, quantum-, nano- and bio-technology depends more than ever on a profound understanding of the inner workings of tailored materials as we have seen in our research on quantum materials. This truth extends all the way from the macroscopic down to nanometer length scales. However, the elementary building blocks of condensed matter at the smallest scales are in constant motion. Therefore, pure microscopic still images lack the information about their time evolution. To correlate and understand how function of materials arises from microscopic dynamics, ultrafast videos of the nanoworld are essential.

In our group, we have gained a broad expertise in tracing the dynamics in condensed matter systems on ultrafast timescales. At the same time, we have pioneered developments for novel microscopy techniques that combine extraordinary temporal resolution with nanometer and sub-nanometer spatial resolution.

We use sharp metallic tips in combination with ultrashort laser pulses to trace either a tunneling current (so-called "light-wave scanning tunneling microscopy") or the scattered near-fields below the tip ("ultrafast near-field microscopy" or "time-resolved polarization nanoscopy").

In both areas we have seen breakthroughs and are working on the next steps towards better resolution and a deeper understanding of different material systems.

Selection of breakthrough publications

We traced the motion of a single molecular orbital upon charging

T. L. Cocker et al., Nature 539, 263–267 (2016)

We followed the tunneling of single charges across an atomically thin junction

M. Plankl et al., Nature Photonics 15, 594–600 (2021)

We developed an ultrafast polaritonic switch

M. A. Huber et al., Nature Nanotechnology 12, 207–211 (2017)

We coherently controlled a single molecule switch with ultrafast atomic-scale forces

D. Peller et al., Nature 585, 58–62 (2020)

We investigated the surface states on topological insulators

F. Mooshammer et al., Nano Letters 18, 7515–7523 (2018)

We traced an electromagnetic wave confined to the atomic scale

D. Peller et al., Nature Photonics 15, 143–147 (2021)

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