Within a project supported by the German Ministry for Education and Research (BMBF) the IFSW has demonstrated an ultrafast multi-pass thin-disk laser amplifier generating an average output power of 1.1 kW, an almost diffraction limited beam quality and an optical efficiency of 44%. With a repetition rate of 800 kHz, the energy of the 7.3 ps long pulses was 1.38 mJ. This shows for the first time that ultrafast lasers with > 1 kW of average output power and > 1 mJ of pulse energy are feasible, which paves the way for significant progress in many applications especially for materials processing.
The seed laser was a commercial ultrafast thin-disk laser with 80 W of average power from Trumpf. The multi-pass thin-disk laser amplifier was pumped at a wavelength of 969 nm in the zero-phonon transition. The pulses are amplified by 40 passes through the approximately 130 µm thin Yb:YAG disk and the system does not require chirped pulse amplification or any recompression of the pulses.
More details are published in J.-P. Negel et al, Optics Letters 38 (24), 5442-5445 (2013).
Contact: Dr. Marwan Abdou Ahmed