Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 18: Laser Development: Solid State Lasers II
Q 18.7: Vortrag
Dienstag, 9. März 2010, 15:30–15:45, F 128
Multiple active mirror concept for high energy short-pulse lasers — •Markus Loeser, Franziska Kroll, Fabian Röser, Mathias Siebold, Ulrich Schramm, and Roland Sauerbrey — Forschungszentrum Dresden-Rossendorf e.V., Dresden,Germany
Ytterbium-doped gain media are preferably utilized in high-energy, diode-pumped lasers due to their comparably long fluorescence lifetime, absence of excited state absorption, and quenching effects. Despite exhibiting a low quantum defect, thermal lensing and stress birefringence within the amplifying medium limits the maximum repetition rate of large aperture lasers. Furthermore, the quasi-three-level scheme of Yb3+ leads to re-absorption losses at room temperature especially when operating at low fluences. Here, we present a novel approach combining longitudinal cooling of a disk-laser design with the energy storage capability of a rod amplifier. Therefore, a multiple active mirror amplifier is presented for improved optical-to-optical conversion efficiency and reduced thermally induced aberrations at high repetition rates. Multi-passing both pump and extraction beams through the gain medium, which is well known from thin-disk lasers, also reduces the re-absorption losses. However, energy scaling of a single thin-disk design is limited by parasitic lasing due to a high aspect ratio between longitudinal and transverse gain. We also introduce simulation results on a multiple active mirror short-pulse amplifier employing various Ytterbium-doped gain media such as Yb:YAG, Yb:CaF2, Yb:glass, and Yb:silica. Furthermore, time resolved measurements of thermally induced aberrations at pulse-pumped operation are illustrated.