Karl-Scheel-Sitzung und Preis 2010
Zeit
Sprecher:innen
- Dr. Olga Smirnova
Dateien
High harmonic spectroscopy of small molecules
Im Rahmen der Karl-Scheel-Sitzung 2010 wurde
Frau Dr. Olga Smirnova,
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie Berlin,
in Anerkennung ihrer hervorragenden Forschungsarbeiten auf dem Gebiet der
Spektroskopie von kleinen Molekülen mittels höherer Harmonischer
der Karl-Scheel-Preis 2010 verliehen.
Die Preisträgerin hielt einen Vortrag über ihre Forschungsergebnisse.
Im Anschluss erfolgte die Verleihung des Karl-Scheel-Preises an die Vortragende.
High harmonic emission occurs when an electron, liberated from a molecule by an incident intense infrared laser field, gains energy from the field and recombines with the hole left in the molecule. High harmonic spectroscopy combines sub-Angstrom spatial and attosecond (1 asec=1018 sec) temporal resolution. The spatial resolution originates from the de-Broglie wavelength of the recombining electron, while the temporal resolution is due to the attosecond duration of the recombination event.
In the language of pump-probe spectroscopy, strong-field ionization acts as a 'pump' and recombination acts as a 'probe'. Recombination occurs within a fraction of the laser cycle after ionization. The time of ionization is linked to the recombination time, the latter is mapped onto the harmonic number. The shape of the hole at the time of recombination determines the harmonic amplitudes, phases and polarizations. Thus, each harmonic makes a snapshot of the hole dynamics for a different 'pump-probe' delay, providing a 'frame' for the attosecond 'movie'. The time interval between the frames, which is about 100 asec, determines the temporal resolution.
I will demonstrate how one can decode a 'harmonic movie' and reconstruct the initial shape of the hole upon strong field ionization and its further dynamics for different molecules, gaining insight into the attosecond dynamics of the multi-electron rearrangement in strong laser fields.
