Type: Zeitschriftenaufsatz (reviewed)
We report on a high power ultrashort pulse regenerative amplifier system, entirely based on thulium-doped laser materials operating around 1.94 μm. At a repetition rate of 1 kHz the Tm:YAP regenerative amplifier emits pulse energies > 700 μJ, only limited by the damage threshold of the Tm:YAP crystal. The pulses can be compressed to 380 fs at an efficiency of 50 \%. Purging of the regenerative amplifier cavity with nitrogen is necessary due to atmospheric absorptions causing long ps pedestals in the autocorrelation.