Attosecond PulseTrains and Electronic Dynamics

With a multi-cycle driving laser, the produced high harmonics are a train of attosecond pulses in time domain. We plan to generate very intense attosecond pulse trains (APTs) and use these APTs to study nonlinear response of atoms, molecules and material in attosecond domain. A high repetition rate (1 khz), high pulse energy (20mJ/pulse) ultrafast laser system will be used to produce micro-joule harmonics in EUV regime. The system of interest include correlated double ionization, charge transfer in polyatomics and photoionization induced electron relaxation.

Schematics of temporal profile of two APTs with the time separation of (a) T and (b) 2T. 2T (2.6 fs for 800 nm laser) separation can be achieved by adding small amount of second harmonic to the fundamental driving laser. t is the closest time delay between pulses in 2 APTs.