Germán Sciaini is a world expert in the field of ultrafast structural dynamics. He is developing state-of-the-art instrumentation to capture atoms in motion. He heads the Ultrafast Electron Imaging Laboratory, home of a time-resolved electron diffraction setup and an ultrafast high-resolution electron microscope. Germán holds the Canada Research Chair in Atomically Resolved Dynamics and Ultrafast High-Resolution Imaging. Femtosecond electron diffraction Time-resolved structural dynamics Ultrafast high-resolution electron imaging Strongly correlated materials Membrane channels Health and Safety committee member, 2015 2006 Ph.D. Chemistry (Physical-Chemistry), University of Buenos Aires, Argentina 2001 Licenciado en Ciencias Químicas, School of Sciences, University of Buenos Aires, Argentina

Ultrafast lasers provided the “first light” in sufficiently short pulses to monitor atomic motion on the relevant timescales; below a millionth of a millionth of a second, to literally catch atoms on the fly as in stop-motion photography. However, the spatial resolution in optical microscopy is limited to about the size of a big virus. This is about ten thousand times too coarse to observe the molecular structure at its finest detail, down to its fundamental building blocks – atoms. The progress in the development of ultrafast structure-sensitive cameras over the last 20 years has been tremendous, with large scale, kilometers long facilities such as LCLS (Stanford) built to provide us with the temporal and spatial resolutions required to observe atoms in motion. Germán's group at University of Waterloo develops such “atomic-level” cameras based on the use of ultrashort electron bursts. The main two directions in the group involve the determination of molecular structure and dynamics with atomic spatial resolution. Only 50 years ago, transition states, bond breaking and bond formation events were thought to be immeasurably fast. Nowadays, we have reached the spatial and temporal resolutions required to observe atoms in motion and, with that, been able to provide the most fundamental understanding of dynamical phenomena relevant to physics, chemistry, and biology.

Our group develops and applies ultrafast electron sources to access molecular structure and dynamical phenomena with atomic spatial resolution. We can literally see atoms move!

Ultrashort and ultrabright electron bursts for time-resolved diffraction.

FED Setup In ultrafast electron diffraction a femtosecond (fs) optical pulse excites the sample and an ultrashort electron bunch probes the photoinduced structural changes. The atomic motions are recorded by time-delaying diffraction patterns with respect to the “clocking” excitation pulse. This technique builds on the concept of stop-motion photography, which dates back to 1870.

Coherent electron sources for high-resolution single biomolecule imaging.

Tip Source Ultrafast electron sources are being developed to perform high-resolution electron imaging of single proteins and aperiodic systems.

M. Hada, D. Zhang, K. Pichugin, J. Hirscht, M. A. Kochman, S. A. Hayes, S. Manz, R. Y. N. Gengler, D. A. Wann, T. Seki, G. Moriena, C. A. Morrison, J. Matsuo, G. Sciaini & R. J. D. Miller*, “Cold ablation driven by localised forces in alkali halides”. Nature Commun. 5, 3863 (2014). M. Gao†, C. Lu, H. Jean-Ruel, L. C. Liu, A. Marx, K. Onda, S-y. Koshihara, Y. Nakano, X. Shao, T. Hiramatsu, G. Saito, H. Yamochi, R. R. Cooney, G. Moriena, G. Sciaini† & R.J.D. Miller*. “Mapping Molecular Motions Leading to Charge Delocalization with Ultrabright Electrons” (†equal contributions) Nature 496, 343 (2013). M. Gao, H. Jean-Ruel, R. R. Cooney, J. Stampe, M. de Jong, M. Harb, G. Sciaini, G. Moriena & R.J.D. Miller*, “Full Characterization of RF Pulse Compressed Femtosecond Electron Pulses using Ponderomotive Scattering”. Opt. Express 20, 12048 (2012). G. Moriena, M. Hada, G. Sciaini, J. Matsuo and R.J.D. Miller*, “Femtosecond Electron Diffraction: Preparation and characterization of (110)-oriented bismuth films”. J. Appl. Phys. 111, 043504 (2012). M. Eichberger†, H. Schäfer†, M. Krumova, M. Beyer, J. Demsar, H. Berger, G. Moriena, G. Sciaini† & R.J.D. Miller*, “Snapshots of Cooperative Atomic Motions in the Optical Suppression of Charge Density Waves”. (†equal contributions). Nature 468, 799 (2010).