Development of a Joule‐class Yb:YAG amplifier and its implementation in a CPA system generating 1 TW pulses

In this paper the development and implementation of a novel amplifier setup as an additional stage for the CPA pump laser of the Petawatt Field Synthesizer, currently developed at the Max-Planck-Institute of Quantum Optics, is presented. This amplifier design comprises 20 relay-imaged passes through the active medium which are arranged in rotational symmetry. As the gain material, an in-house-developed Yb:YAG active-mirror is used. With this setup, stretched 4ns seed pulses are amplified to output energies exceeding 1J with repetition rates of up to 2Hz. Furthermore, a spectral bandwidth of 3.5nm (FWHM) is maintained during amplification and the compression of the pulses down to their Fourier-limit of 740fs is achieved. To the best of our knowledge, this is the first demonstration of 1TW pulses generated via CPA in diode-pumped Yb:YAG.