FEMTOELEC · Innovative Femtosecond laser-plasma based electron source for studying ultrafast structural dynamics

How do atoms move in a solid? How long does it take for a phase transition to occur or for a molecule to change its configuration? These are some of the fundamental questions that the field of ultrafast science asks and attempts to answer. Understanding these ultrafast processes in complex matter at the atomic scale requires advanced sources of radiation: X-rays or electrons with sub-angstrom wavelength and femtosecond duration.In the past decade, such sources have become available, allowing scientists to obtain a first glimpse into the ultrafast world, with the direct observation of atomic motion or structural changes in matter. Until now however, the time resolution has not allowed us to study the fastest processes and has limited our window of observation to processes slower than 100 femtoseconds.To overcome this limitation, this proposal introduces a new method based on laser-plasma interaction for producing an electron source with shorter duration. The project will explore laser-plasma interaction in a new regime: low energy, high-repetition, few-cycle laser pulses interacting with a plasma for producing femtosecond electron bunches with parameters relevant for probing matter with electron diffraction. It will take advantage of the very high accelerating gradients that plasmas can sustain for accelerating electrons to relativistic energies in micrometer lengths.This novel electron source will be implemented in diffraction experiments for probing structural dynamics in condensed matter with angstrom spatial resolution and unprecedented time resolution. This table-top innovative electron source has the potential to overcome the limitations of current ultrafast electron diffraction and could offer new insights for transdisciplinary applications in condensed matter physics, chemistry and biology.