Berlin 2005 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

Q: Quantenoptik und Photonik

Q 54: Anwendung ultrakurzer Lichtimpulse II

Q 54.4: Vortrag

Dienstag, 8. März 2005, 18:15–18:30, HU 1070

Dynamics of femtosecond laser-induced breakdown in water — •Cristian Sarpe-Tudoran, Andreas Assion, Matthias Wollenhaupt, Marc Winter, and Thomas Baumert — Universität Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany

Femtosecond laser induced optical breakdown in water has been intensively investigated in the last decade due to its applications in precise ablation of biological tissues, therapeutic laser medicine and laser analytic. Even if it is generally accepted that the primary process in the laser induced optical breakdown is the generation of high-density free electrons by multiphoton and impact ionisation, the free electrons plasma evolution in the early times of formation is not yet completely understood. We used a combination of imaging techniques, transient reflection spectroscopy and frequency-domain interferometry in order to monitor the early time breakdown plasma dynamics and to study its dependence on the laser intensity. We observed that the optical properties of the breakdown plasma created by femtosecond lasers on a water surface are quite similar to that of a Fabry-Perot interferometer. Therefore the dynamics of the plasma thickness in the nm-range and the temporal evolution of the free electrons density can be deduced.