Compact Sub-Picosecond Multi-mJ Multi-kHz Yb:YAG Amplifier

The development of multi-mJ pump sources with kHz repetition rates for OPCPA systems based on Yb:YAG regenerative amplifiers is nowadays realized using chirped-pulse amplification (CPA) [1,2]. These systems avoid nonlinear optical effects by reduction of the peak intensity at the expense of introducing large amounts of group delay dispersion (~108 fs2) into the seed beam. We show a novel laser architecture forgoing CPA and using a combination of regenerative amplification and a multipass amplification geometry resulting in a more compact and cost effective laser source than it is possible by current systems based on CPA. To reduce nonlinear contributions to a minimum, this hybrid is based on an Yb:YAG thin-disk aiming for 15–20mJ output pulse energy in the near future, limited only by the damage threshold of the optics. Together with post amplification in an additional thin-disk multipass amplifier [3] we propose a competitive alternative to commonly available systems based on CPA delivering 100–200mJ.