Hamburg 2009 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 10: Ultrakurze Pulse: Erzeugung I

Q 10.2: Vortrag

Montag, 2. März 2009, 14:15–14:30, VMP 8 R206

Femtosecond supercontinuum generation in a feedback cavity: Experimental investigations on nonlinear dynamics — •Nicoletta Brauckmann, Michael Kues, Till Walbaum, Petra Groß, and Carsten Fallnich — Institut für Angewandte Physik Westfälische Wilhelms-Universität, Münster, Deutschland

Supercontinuum generation is a highly nonlinear optical phenomenon where narrow bandwidth light becomes spectrally broadband due to, e.g., self-phase modulation, four-wave mixing, soliton fission and Raman scattering. For a high degree of pulse-to-pulse coherence in supercontinua typically short pulses with only a few tens of femtoseconds are used. Currently we are investigating how an optical feedback allows to relax the experimental conditions for low-noise supercontinuum generation. In our experimental feedback system, the supercontinuum is generated in a photonic crystal fiber within a ring cavity. This leads to an interaction of the supercontinuum with the following pulses of the titanium:sapphire pump laser. Here, we present the nonlinear dynamical behaviour of this system which includes, e.g., regimes of period doubling, which means that the system state is not reproduced after every cavity roundtrip, but after every second roundtrip. In our experiments, we also observe system state reproductions after three and four roundtrips and more complex regimes of operation up to chaos. With our investigations we want to identify regimes of operation where parts of supercontinuum show improved pulse-to-pulse coherence related to self-stabilisation mechanisms.