CPA-free amplification of sub-10 ps pulses in Ho:YLF to the mJ-level at 2 µm wavelength

The generation of sub-10 ps pulses around a wavelength of 2 µm with pulse energy at millijoule-level in a compact CPA-free amplifier chain is presented. This laser source covers a broad range of pulse repetition frequencies from 1 to 100 kHz with a pulse peak power from 136 to 17MW, respectively. We used highly doped Ho:YLF crystals to achieve an overall amplification factor of almost 52 dB. A characterization of these crystals regarding upconversion losses and attainable small-signal gain supports this work.