APPLI group (Application of ultrafast sources to solid state physics)



 The APPLI group is dedicated to the development of new femtosecond particle and radiation sources and to their use for probing ultrafast dynamics in solids. We put a special emphasis on developing high-repetition rate and reliable sources that can truly be used for probing ultrafast phenomena at the femtosecond time scale. 

The group has two main activities:

  • Part of the group is focused on material science: we are interested in the dynamics of electrons, spins, phonons and their mutual couplings. We want to understand the relaxation pathways that energy can take in a crystal and also to explore the possibility of photoinducing phase transitions. These studies are based on pump-probe techniques using femtosecond lasers. We explore ultrafast processes in a large range of materials, from metals to strongly correlated systems and nanomaterials. More practically, the group has developed a femtosecond pump-probe spectroscopy set-up with visible and Infra-Red photons. We also have a high-harmonic generation platform which delivers femtosecond Ultra-Violet light for probing the ultrafast dynamics of the magnetization in solids.
  • Another part of the group is pushing the development of innovative femtosecond electron source. Femtosecond electrons can be used to probe structural dynamics in solids via ultrafast electron diffraction (UED). UED permits to directly access atomic motion and it is an ideal technique for vizualizing ultrafast structural dynamics. We are currently developing a new technology, based on the interaction of ultrashort lasers with plasmas, for producing the shortest electron bunches for probing matter.




ENSTA CNRS Ecole Polytechnique