Analysis of Ho ³⁺ :LuLiF ₄ in a Q-switched laser resonator for high pulse peak power

Two Ho 3+ :LuLiF 4 lasers for operation in continuous wave (cw)- and Q-switched regimes are presented. Efficient cw-operation is reported with a maximum output power of 27.6 W and a beam quality factor M 2 < 1.2. No significant thermal effects on limiting output power and beam quality have been found. Q-switched operation resulted in a pulse energy of 30 mJ, pulse width under 17 ns, and pulse peak power of 1.78 MW while maintaining an M 2 < 1.1. For further investigation, the thermal lens effect in Ho 3+ :LuLiF 4 is approximated. Pulse width jitter is reported to be below 5% for pulse repetition rates of 100 Hz.