Energy scaling of Kerr-lens modelocked Ho

We demonstrate peak power and pulse energy scaling of Kerr-lens modelocking (KLM) Ho:YAG thin-disk lasers (TDLs) emitting at 2.1-\(\mu\)m wavelength. We compare different laser configurations to reach a maximum pulse energy of 1.7 \(\mu\)J at an output power of 29 W with a pulse duration of 434 fs, corresponding to a peak power of 3.7 MW. This represents a 5-fold increase in pulse energy and 4-fold increase in peak power compared to previously demonstrated KLM Ho:YAG TDLs, thus reaching record high peak power for 2.1-\(\mu\)m modelocked oscillators. We discuss current limitations at this wavelength and guidelines for future work towards higher power and pulse energies.