Single-stage Yb:YAG booster amplifier producing 2.3 mJ, 520 fs pulses at 10 kHz (Orale)

Julien Pouysegur (1, 2) , Florent Guichard (1, 2) , Birgit Weichelt (2) , Martin Delaigue (2) , Yoann Zaouter (2) , Clemens Hönninger (2) , Eric Mottay (2) , Patrick Georges (1) , Frédéric Druon (1)

1 Laboratoire Charles Fabry / Lasers
2 Amplitude Systèmes

520fs, 2.3-mJ pulses are demonstrated in a Yb:YAG booster amplifier delivering peak powers up to 4.4GW. To avoid damage and nonlinear-effect issues, passive divided pulse amplification is studied for the first time for bulk-amplifier. Great efforts have been deployed in the development of laser systems delivering femtosecond pulses for industrial and scientific applications. Among all available technologies, fiber lasers came out as one of the best choice due to their capability to deliver short pulse duration (typically 300 to 500 fs) together with high average power within very reliable and robust systems. Nevertheless, one of the main drawbacks remains the limited output energy available for such laser due to the strong confinement of the light. Standard femtosecond fiber lasers can deliver typically up to 10s µJ energy pulses; and lasers based on rod type technology allow to reach up to the mJ level for laboratory systems [1-2] and 200 µJ for industrial systems. We propose here to enhance the energy from fiber sources by implementing a very simple, but optimized, Yb doped YAG booster stage. This booster consists in using a cm-long crystal to have a simple high gain booster together with a rather-modest length to prevent from deleterious nonlinear effects like self-phase modulation and critical self-focusing. Secondly, the use of a simple and passive divided pulse amplification (DPA) setup [3] is also investigated, in order to exceed the energy limitation. We investigate how the DPA permits to overcome the laser threshold limits from 2.9 mJ to 4.1 mJ. This simple and straightforward amplifier geometry allows to deliver, in a nominal and safe regime, ultrashort pulses below 520fs for energy of 3mJ (before compression) 2.3 mJ after. We demonstrated then pulses up to 4.4 GW of peak power. The fiber laser source used is a standard industrial laser-developed by Amplitude Systems-that delivers pulse energy 180µJ up to 100 kHz repetition rate with duration of 350 fs. By limiting output energy below 200µJ, nonlinear effects and damages threshold in the laser are safely avoid. The Yb:YAG booster is implemented between the fiber amplifier and the compressor

Mots clés: Laser ytterbium; bulk amplifiers; Ultrafast lasers

Domaines: Optique [physics.optics]

Julien Pouysegur, Florent Guichard, Birgit Weichelt, Martin Delaigue, Yoann Zaouter, et al.. Single-stage Yb:YAG booster amplifier producing 2.3 mJ, 520 fs pulses at 10 kHz (Orale). Advanced Solid State Lasers 2015, Oct 2015, Berlin, Germany. ⟨10.1364/ASSL.2015.AW3A.5⟩. ⟨hal-01359547⟩