Product Code: ICAL06_M206

1 mJ, Multi-Khz, Sub-500 Fs Diode-Pumped Ytterbium Laser Amplifier
Authors:
Antoine Courjaud, Amplitude Systemes; Pessac France
Clemens Hoenninger, Amplitude Systemes; Pessac France
Eric Mottay, Amplitude Systemes; Pessac France
Inka Manek-Hoenninger, University Bordeaux 1; Talence France
Martin Delaigue, University Bordeaux 1; Talence France
Presented at ICALEO 2006

Precision micro machining in an industrial environment demands stable and high performance femtosecond lasers. Up to now most femtosecond amplified systems delivering mJ pulse energies are based on Ti:sapphire as gain medium which require rather complex pump lasers. We demonstrate a directly diode-pumped femtosecond laser amplifier with up to 1 mJ pulse energy and pulse repetition rates up to 5 kHz. Chirped pulse amplification is applied in order to eliminate nonlinear effects and to avoid damage of optical components during the amplification process. The seed pulses of 20-nJ pulse energy and 200 fs pulse duration are temporally stretched using a grating stretcher, amplified inside a regenerative amplifier cavity, and temporally compressed by a pair of diffraction gratings. The use of highly efficient transmission gratings led to an overall compressor transmission of 80%. The amplifier medium was Yb:KYW. We extracted up to 1.25 mJ at a pulse repetition rate of 2 kHz and 0.88 mJ at a pulse repetition rate of 5 kHz. The compressed pulse duration was 480 fs. The beam quality has been measured and gave an M² value of < 1.2.