Dr.
Thomas Pfeifer
University of California-Berkeley,
Lawrence Berkeley National Laboratory
Ultrafast Spectroscopy and Control with Coherent Attosecond Soft-X-Rays:
Novel
Techniques and Applications
Monday, February 18, 2008
4:00 p.m.
Cardwell 102
Recent progress in ultrafast laser technology enables the generation of soft-x-ray pulses down to ~100 attoseconds in duration, thus allowing access to the unexplored realm of electron dynamics. On the other hand, coherent control of matter with shaped laser fields has reached its maturity with regard to controlling the relative motion of atoms in matter (vibrations/phonons, phase transitions, molecular reactions and rotation). However, due to the lack of laser pulse shaping techniques in the soft-x-ray spectral region, coherent control has so far had only limited capability of controlling the electronic wavefunction directly, which is of fundamental importance to physics (multi-electronic correlation) and chemistry (bonding dynamics). In this talk, it will be shown how Coherent Control can be transferred to, and combined with Attosecond Science towards the goal of gaining comprehensive mastery of matter on the quantum scale. Experimental results, theoretical concepts, and simulations will be presented that demonstrate the feasibility of using a) multicolor laser fields [1], b) phase-shaped laser pulses [2], and c) medium control [3] in high-harmonic generation to generate coherent shaped broadband (multi-electronvolt bandwidth) light fields, that enable shaping of pulses and pulse trains in the attosecond soft-x-ray domain. Also, the first experimental application of shaped coherent soft-x-rays towards the optimal control of electronic quantum processes (dissociative photoionization of SF6) will be presented [4]. Finally, I will outline the design for a novel ultrafast spectroscopic technique that will provide direct and time-resolved information on the correlated motion of electrons on the attosecond time scale.
References:
[1] T.P. et al. Phys.
Rev. Lett.
97, 163901 (2006)
[2] T.P. et al. Opt. Lett.
30,
1497 (2005)
[3] T.P. et al. Opt. Express
15,
17120 (2007)
[4] T.P. et al. Opt. Express
15,
3409 (2007)