High-gain Ho:YLF sub-nanosecond system seeded by a gain-switched laser diode

We demonstrate a high-gain Ho:YLF sub-nanosecond laser system utilizing a gain-switched laser diode as the seed source. The 1.0 kHz pJ-level seed from the gain-switched laser diode is first amplified to 1.1 mJ by a Ho-doped fiber preamplifier with a gain of 30 dB and a regenerative amplifier (RA) with a gain of 60 dB. By adding a single-pass amplifier, the pulse energy is further extended to 7.5 mJ. A pulse duration of 518.5 ps was achieved, which is symmetrical with no tail or sub-peaks. The root mean square (RMS) stability of the output energy of the entire system over a 0.5 h period is 2.11%. This method provides a reliable and simple way to directly obtain high-energy 2.05 µm sub-nanosecond lasers.