Amplifier_final.pdf (1.51 MB)
A compact 20-pass thin-disk multipass amplifier stable against thermal lensing effects and delivering 330 mJ pulses with M² < 1.17
preprintposted on 2023-09-27, 09:23 authored by Manuel Zeyen, Lukas Affolter, Marwan Abdou Ahmed, Thomas Graf, OGUZHAN KARA, Klaus Kirch, Miroslaw Marszalek, Francois Nez, Ahmed Ouf, Randolf Pohl, Siddharth Rajamohanan, Pauline Yzombard, Karsten Schuhmann, Aldo Antognini
We report on an Yb:YAG thin-disk multipass amplifier delivering 50 ns long pulses at a central wavelength of 1030 nm with an energy of 330 mJ at a repetition rate of 100 Hz. The beam quality factor at the maximum energy was measured to be M² = 1.17. The small signal gain is 20, and the gain at 330 mJ was measured to be 6.9. The 20-pass amplifier is designed as a concatenation of stable resonator segments in which the beam is alternately Fourier transformed and relay-imaged back to the disk by a 4f-imaging optical scheme stage. The Fourier transform propagation makes the output beam robust against spherical phase front distortions, while the 4f-stage is used to compensate the thermal lens of the thin-disk and to reduce the footprint of the amplifier.