High-power CW and passively Q-switched laser operation of Yb:GdCa4O(BO3)3 crystal

• CW output power of 18.2 W is produced with optical conversion efficiency of 55%.
• Q-switched output power of 15.6 W is generated at 91 kHz.
• Laser pulses of 737 μJ in energy and 3.6 ns in duration are generated at 5.7 kHz.
• Peak power amounting to 205 kW.

We demonstrate efficient high-power CW and passively Q-switched operations of Yb:GdCa4O(BO3)3 lasers. An output power of 18.2 W is generated at 1031.5 nm in CW mode, with optical-to-optical and slope efficiencies being respectively 55% and 70%, with respect to incident pump power. In passively Q-switched operation with a Cr4+:YAG crystal as saturable absorber, a maximum average output power of 15.6 W is produced at a pulse repetition rate of 91 kHz, with an optical-to-optical efficiency of 44%. Low-repetition-rate Q-switched action is also realized, generating an average output power of 4.2 W at 5.7 kHz, the resulting pulse energy and duration are 737 μJ and 3.6 ns, leading to a peak power amounting to 205 kW.