Visualizing electrons in real-space and real-time

Place: Online

Zoom link: https://nanoscience-imdea.zoom.us/j/97284156746?pwd=M0o2NW5ma0ZRYzNaRjZDRHZCRGxCUT09

ID: 972 8415 6746
Password: DNKP8q

Abstract:
Electron dynamics in molecules evolve on very fast time scales and are
spatially confined to sub-molecular volumes. Therefore, in order to
understand and control chemical transformations, it is required to
explore electronic motion with attosecond temporal and picometer spatial
resolutions simultaneously. Ultrashort laser pulses allow visualizing
electron dynamics in molecules at its natural time scale, at the prize
of spatial averaging over the laser interaction volume. Information from
the spatial domain is retrieved from reconstruction algorithms. On the
other hand, scanning tunneling microscopy (STM) offers the possibility
to investigate the real-space domain with atomic scale resolution,
although with poor time resolution limited by the control electronics
that move the scanning tip. Here I will show that the extreme
confinement of ultrashort laser electric fields inside the tunnel
junction of an STM results in a laser-induced tunneling current that can
be used to locally map ultrafast electronic processes at their natural
space and time scales. I will present the first fully experimental
“movie” of the oscillation of electrons between molecular electronic
states. To extend the applicability of Ultrafast-STM to study
vibrational modes of molecules I will also present the development of
ultrashort pulse excited Tip Enhanced Raman Spectroscopy (TERS) with 500
fs laser pulses. This technological advancement has the potential to
combine sub-picosecond time resolution, atomic scale spatial resolution
and meV energy resolution simultaneously.