Max-Planck-Institut für Kernphysik Heidelberg

Atoms and molecules in ultra-short laser pulses

Priv.-Doz. Dr. Robert Moshammer

  Research topics:  |  Ions in Traps  |  Electrons in Collisions  |  Lasers in Time  |  
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Short and ultra short laser pulses

The processes of all chemical reactions are based on unimaginably fast movements: Atomic nuclei are vibrating around their equilibrium positions, binding electrons are moving into other orbitals, atomic nuclei and electrons are rearranging such that the educts finally form a new compound. All this happens within only a few femtoseconds (10-15 s) or even attoseconds (10-18 s) - fractions of a second which are so tiny compared to a whole second like a second compared to the age of our universe. The investigation of these processes in atoms and molecules provides a detailed understanding of the rules that govern material world around us. It is also a goal, however, some day to be able to influence or even to precisely control the outcome of chemical reactions. In order to reach this aim, pulsed intense lasers in combination with highly precise particle detection systems, so-called reaction microscopes, are employed at the Max Planck Institute for Nuclear Physics.

At the FLASH facility in Hamburg we do experiments with the free electron laser like few- or one-photon multiple ionization of rare gas atoms.


Part of the femtosecond laser setup
(pulse compression)

Femtoseconds dynamics

We study fundamental processes of atoms and molecules exposed to intense and ultrashort laser pulses.
By combining a Ti:Sa laser system which creates 6fs laser pulses with a Reaction Microscope we are able to detect all outgoing fragments (ions and electrons) in coincidence and can reconstruct the complete three-dimensional momentum vectors of all charged particles with very high accuracy.

Attosecond dynamics

For certain problems in present-day research, the temporal resolution which can be attained using femtosecond lasers, is no longer sufficient, for example, when it is intended to observe the motion of electrons in an atom. For this reason, physicists in a considerable number of research institutes are intensively searching for possibilities to produce light pulses of even shorter duration.

Free Electron Lasers

When a packet of about one billion electrons is sent through an arrangement of magnetic fields with alternating field direction, a so-called undulator, it describes oscillating tracks and these accelerated charges thereby emit light – the synchrotron radiation. In this way it is possible to generate intensive radiation with energies up to the hard X-ray region.


Development of fast acqisition and analysis procedures for REMI data.

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