Düsseldorf 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
Q: Fachverband Quantenoptik und Photonik
Q 19: Erzeugung ultrakurzer Lichtimpulse
Q 19.1: Vortrag
Dienstag, 20. März 2007, 10:30–10:45, 5K
Fourier limited tunable pulses in the visible and NIR by cw seeding of fs and ps NOPAs — •Markus Breuer1, Christian Homann1, Eberhard Riedle1, and Frank Setzpfandt2 — 1LS für BioMolekulare Optik, LMU München — 2Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena
Optical parametric amplifiers (OPAs) seeded by a continuum or a parametric generator are the prime source of tunable ultrafast radiation. They do, however, not render pulses with a clean Gaussian spectrum and a pulse length given by the Fourier limit. In the nanosecond regime superior pulses are generated by amplification of monomode cw seed light in dye amplifiers and optical parametric oscillators. For the ultrafast regime the principle has so far not been exploited, due to the small number of seed photons contained within the temporal amplification interval. Yet, the ever increasing availability of low cost diode sources would make it an attractive method. We have succeeded to operate cw seeded 2-stage noncollinear OPAs (NOPAs) with a 150 fs Ti:sapphire pump source and a 10 ps Nd:VAN system. A few hundred μJs of pump energy at 1 or 5 kHz led to a few μJs of output with single mWs of seed power. The fs NOPA rendered 88 fs pulses at 532 nm with a bandwidth of 6 nm (time bandwidth product of 0.55) from about 500 seed photons. For ps operation the lower damage threshold of the BBO amplifier crystals for ps pulses had to be overcome by long crystal lengths. The resulting ps NOPA was tunable over a wide range in the NIR by tuning the fiber coupled seed and had a spectral bandwidth of only 0.86 nm (at 1.53 um) with a clean Gaussian distribution.