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Laser Amplification via Stimulated Brillouin Scattering in the Strongly Coupled Regime: Towards Control and Optimization

Marco Chiaramello (LULI)

The use of plasma as an amplification medium is currently discussed because it can overcome current solid-state technology limitations in terms of maximum achievable intensity. Via parametric scattering off a plasma oscillation the energy from a long pump pulse can be transferred into a short seed pulse. Strong Coupled Brillouin scattering has the potential to become a robust amplification process.

In this thesis we present theoretical and numerical (PIC) studies aimed at better understanding the role of each plasma parameter on the amplification mechanism and, more generally, on the energy transfer between two laser pulses counter-propagating in a plasma: the interaction length, the shape of the density profile, the duration of the long pump signal, the relative delay between the seed and pump signals, the chirp of the long pump laser pulse. We show a first complete description of the time and space evolution of the phases of the pump, seed and plasma density perturbation that dictate the energy flow transfer between the pump and seed laser beams and the efficiency of amplification. In order to propose and improve nowadays experimental set-ups, a comparison with recent experiments is performed.