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Slow electrons from fast activation with intense laser pulses

Event Details

Event Dates: 

Wednesday, August 5, 2015 - 11:00am

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Prof. J.M. Rost

Speaker Affiliation(s): 

PULSE Institute, Stanford University, Max Planck Institute for the Physics of Complex Systems
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Public Seminar

Event Details & Abstract: 

While ultracold physics naturally deals with slow particles, it may be surprising that “hot” electron dynamics activated by intense and short laser pulses also leads to slow electrons with pronounced features.

First, we will discuss photo ionization of atoms and molecules with intense laser pulses in the mid-infrared regime. The photo electron spectra reveal slow electrons with universal but very distinct dynamical characteristics, giving rise to the so called “Low Energy Structure” (LES), “Very Low Energy Structure” (VLES). We have developed a fully analytical theory including laser focus averaging which predicts the LES as a function of laser pulse length in very good agreement with recent experiments from the Ohio group (diMauro and Agostini). A third so called “Zero Electron Structure” (ZES) is the consequence of non-trivial  electron focusing in the dynamics of the ultraslow electron extracted by a weak electric field and measured at a specific time-delay in the experiment, as recent work together with the experimental group from Frankfurt (Dorner) shows.
Time permitting, the second part of the talk will introduce the so called “envelope hamiltonian”.  It allows for the first time to treat electron dynamics triggered by ultrashort pulses by quantum perturbation theory. Thereby, the non-adiabatic nature of slow electrons created with such pulses can be characterized and understood with a fresh perspective on coherent control by shaping the pulse envelope only.