Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 35: Erzeugung ultrakurzer Lichtimpulse

Q 35.8: Vortrag

Dienstag, 8. März 2005, 12:30–12:45, HU 1070

A Ti:Sapphire laser system with high, variable repetition rate and pulse energy up to 1 mJ — •Thorben Haarlammert, Jana Hüve, Torsten Steinbrück, Grigorios Tsilimis, and Helmut Zacharias — Physikalisches Institut, WWU, 48149 Münster

The generation of High Harmonics or hard X-rays requires both ultrashort pulses and high pulse energies. Furthermore, high repetition rates are of special interest to reach higher average power and higher counting rates.

For these aims a Ti:Sapphire oscillator-amplifier system whose high, variable repetition rate is adjustable between 1–20 kHz has been developed. In the oscillator we use cavity dumping to realise these rates. Output coupling efficiencies of up to 45% are reached. The obtained wavelength spectrum of the oscillator has a FWHM of 80 nm.

The amplification principle is chirped pulse amplification. The pulse width is stretched in time by using an SFL57 crystal. A multipass configuration is used with 8–10 passes of the oscillator beam through the Ti:Sa crystal. Subsequently, the pulse is recompressed by a prism compressor. The Ti:Sa crystal is cooled by liquid nitrogen to ca 95 K to avoid the thermal lens formed by the pump laser.

With this oscillator-amplifier system we have an output energy of 1 mJ at a repetition rate of 5 kHz. First experiments of the generation of High Harmonics with this tool are demonstrated.