Experimental investigation of identical wavelength short light pulses crossing in underdense plasma

摘要

Energy transfer between a long (3-10 ps) "pump" pulse and a short (400 fs) "seed" one, both at a wavelength of 1.057u m quasi counterpropagating in an underdense preformed plasma and produced from the ionization of a gas jet, was observed. Numerical simulations reveal that the energy transfer is due to the coupling involving ion acoustic waves excited in the Stimulated Brillouin Backscattering in the strong coupling regime. The plasma characteristics were tailored using a high-energy ionization laser beam and the plasma density was controlled using a Thomson scattering diagnostic. The energy exchange was observed for different gas (ion) types, pressures (plasma densities), polarization and intensities of the interacting beams.