École Nationale Supérieure de
Techniques Avancées

Abstract

The topic of this thesis work is the modeling and the control of processes occurring during amplification in a chirped pulse laser system. We present the models used, which take into account the propagation, non linear and thermal effects appearing in laser chains based on chirped pulse amplification. An experimental validation of these models demonstrates the importance of spatial effects to obtain a precise modeling of the amplification process. Propagation calculations were made to study the importance of residual aberrations after the correction obtained by a deformable mirror. The use of close loop adaptive correction is shown on the LOA 100 TW laser. This correcting loop is now used daily to improve the spatial and quality and the focal spot of the LOA 100 TW laser. Some studies on spatio-temporal effects created in lens systems were also made. The local delay and the broadening of the global duration, caused by the propagation time delay (PTD) in a lens system, have been measured. These direct measurements of the global temporal broadening are the first to our knowledge. Finally, the future LOA Petawatt laser (LUIRE) was simulated with the previous validated amplification models. We are able to obtain the Petawatt regime (30 J, 30 fs) with an additional multipass amplifier whose characteristics are presented.