Hamburg 2009 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 10: Ultrakurze Pulse: Erzeugung I
Q 10.6: Vortrag
Montag, 2. März 2009, 15:15–15:30, VMP 8 R206
Self-healing mechanism of compressed femtosecond filaments — •Stefan Skupin1, Luc Bergé2, and Günter Steinmeyer3 — 1Max-Planck-Institut für Physik komplexer Systeme, Dresden — 2CEA-DAM, DIF, F91297 Arpajon, France — 3Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie
In self-generated filaments, femtosecond pulses experience strong spatial and temporal shaping effects. The dynamical balance between Kerr self-focusing and plasma-induced defocusing gives rise to a self-guiding mechanism, which involves a complex time dependent radial energy flow (dynamical spatial replenishment). This energy flow strongly links spatial and temporal dynamics.
One of the most surprising properties of femtosecond filaments is on-axis self-compression, i. e., pulse shortening in the center of the beam during filamentary propagation. For examining the self-compression regime, experimental set-ups use windowed cells, allowing for careful optimization of the pressure that gives rise to maximum self-compression. Here we will investigate numerically the influence of these exit windows on pulse propagation, which distort the spatio-temporal shape of the exiting pulse considerably and seem to destroy self-compression. However, upon subsequent propagation in, e. g., the atmosphere, a self-healing mechanism takes place. We find that again, as the self-compression mechanism itself, this self-healing process is a result of a time dependent radial energy flow.