München 2004 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 26: Ultrakurze Lichtimpulse: Erzeugung

Q 26.8: Vortrag

Dienstag, 23. März 2004, 18:15–18:30, HS 223

Tunable sub-10 fs ultraviolet pulses by achromatic second harmonic generation — •Peter Baum, Stefan Lochbrunner, and Eberhard Riedle — Lehrstuhl für BioMolekulare Optik, Sektion Physik, Ludwig-Maximilians-Universität München

Achromatic phase matching was suggested 15 years ago to overcome the bandwidth limitation in second harmonic generation. A broadband light pulse is angularly dispersed such that for all spectral components the phase matching angle of the nonlinear crystal is matched in a fixed overall geometry. Unfortunately this concept has not yet been demonstrated for the generation of extremely short UV pulses. We show that by suitable choice of the prisms used to disperse the visible light from a NOPA all wavelengths between 480 and 900 nm can be phase matched. Experimentally it is shown that a BBO crystal as thick as 360 µ m can be used to frequency double extremely broad visible spectra with about 20 % efficiency. When the UV pulses are compressed in a suitable combination of prisms and slab material tunable pulses with a length well below 10 fs are obtained. The higher order chirp is compensated with a deformable mirror. The precise pulse shape and spectral phase is characterized with ZAP-SPIDER.