The 15.12.2020 at 11h15.
High-Order Harmonic Generation in Structured Materials.
Fabrice Catoire – CELIA (CNRS – Université de Bordeaux, CEA)
In this presentation we will introduce the physical description of the High-Order Harmonic Generation (HHG) induced by a strong IR-midIR pulse interacting with a structured material. After a short introduction of HHG in gas phase explaining the its dynamics and properties , we will show that harmonic cut-off and dynamics is quite different for structured materials . In particular, we will demonstrate that the cut-off law in gas-phase depends linearly on the peak intensity of the laser while for structured materials the cut-off law is proportional to the peak electric field.
In the single active electron frame, we will demonstrate that the so-called intra- and inter-band processes, unraveled by means of the Houston states , are at the origin of the HHG in structured materials. In particular, the cut-off law described earlier can be retrieved with this model. More insight on the dynamics of HHG will be described and discussed.
Finally, we will focus on the intraband process for which a specific resonance condition leading to their generation can be identified by means of the Wannier states. Specifically, it will lead to birth time of the HHG .
 – F. Catoire et al., Phys. Rev. A 96, 063401 (2016).
 – M. Wu et al., Phys. Rev. A 91, 043830 (2015).
 – S. Ghimire et al., Nat. Phys. 7, 138 (2011).
 – F. Catoire and H. Bachau, Phys. Rev. Lett. 121, 143902 (2018).