Propagation effects on attosecond pulse generation

AbstractThis paper is devoted to the dynamics of attosecond pulses created during the high order harmonicgeneration process. In this goal we study Ti:sapphir laser pulses propagating in a H +2 gas. The dynamicsand propagation of the incident pulse is obtained by solving the macroscopic Maxwell equations. Themolecular gas reaction on the electric Þeld, the polar ization, is derived from TDSEOs following the modelpresented in [9], [10]. We are especially interested in this work, in the attosecond pulse dynamics and theintensity of the Þrst harmonics dependently of the p ropagation length inside the gas, on the attosecondpulse generation and propagation and the energy o f return graphs in function of the driver phase. 1 Introdution We are interested in this paper in the attosecond pulse generation and propagation created by high orderharmonic generation [8]. In particular, we study this process by the analysis of the harmonic phases, andtheir behavior depending on the driver phase, using the model presented in [9] and [10] that is a Maxwell-Schr¨ odinger model. It consits in the coupling of the Maxwell and time dependent Schr¨ odinger equationsunder or beyond Born-Oppenheimer. The model is totally nonperturbative, vectorial and multidimensional,taking into account ionization, and high order nonlinearities going far beyond classical nonlinear Maxwell orSchr¨ odinger models. In the one-dimensional case the equations are: