Ho:YLF regenerative amplifier delivering 22 mJ, 2.0 ps pulses at a 1 kHz repetition rate

We report on a high-energy, few-ps, continuous -wave pumped Ho:YLF regenerative amplifier (RA) operating in a chirped -pulse amplification arrangement. A three -stage optical parametric amplifier serves as versatile seed source emitting broadband pulses centered at 2050 nm. It provides seed pulses with 4 mu J energy within the Ho:YLF amplification bandwidth centered at 2051 nm. Thanks to the high seed pulse energy, bifurcation instabilities are mitigated and gain narrowing is reduced for such a high -gain Ho -doped RA operating at few kHz repetition rate. At 1 kHz the Ho:YLF RA emits 22.5 mJ energy pulses with a compressed pulse duration of 2.0 ps in the stable single -pulse regime. The water cooled RA features a high extraction efficiency of 31% and exhibits a remarkable stability of 0.11% rms. Doubling the repetition rate to 2 kHz, RA pulse energy reaches 15 mJ. The demonstrated 10 GW peak power at 1 kHz and the 30 W average power at 2 kHz are the highest values reported to date for few-ps RAs operating at 2 mu m wavelength. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement