André D. Bandrauk
Université de Sherbrooke
6 février 2009 de 16 h 00 à 18 h 00 (heure de Montréal/HNE) Sur place
Interaction of ultrashort intense laser pulses with molecular media leads to highly nonlinear nonperturbative effects which can only be treated by large scale computation on massively parallel computers. Single molecule response to such pulses leads to Molecular High Order Harmonic Generation, MHOHG, (1), from which one can synthesize new "attosecond" pulses necessary to control electron dynamics at the natural time scale of the electron, the attoseocond (10**-18 s), (2).The single molecular response can be obtained from high level quantum Time-Dependent Schršdinger, TDSE, simulations. The collective macroscopic response of a molecular medium requires solving many TDSE,s (>10**5) coupled to the classical laser (photon) Maxwell equations (3). We will present the numerical methods necessary to achieve this goal, especially the problem of transparent and artificial boundary condition techniques in view of the different time scales, photon vs electron. Results will be shown for attosecond pulse generation and pulse filamentation in an aligned molecular medium, the one electron H2+ system(4).
AdresseCRM, Pav. André-Aisenstadt, 2920, ch. de la Tour, salle 6214