Efficient laser operation at 1.06 μm in co-doped Lu3+, Nd3+:GdCa4O(BO3)3 single crystal

• Two crystals of Nd:GdCOB and Nd:GdLuCOB were grown by the Czochralski method.
• The emission cross sections of ZX-cut Nd:GdLuCOB and XY-cut Nd:GdCOB were determined.
• The Nd:GdLuCOB shows higher slope and optical efficiency than Nd:GdCOB crystal.
• We report the first diode-pumped ZX-cut Nd:GdLuCOB laser.

Efficient laser emission at 1.06 μm was obtained from a diode-laser quasi-continuous wave pumped Nd0.04Gd0.86Lu0.10Ca4O(BO3)3 (Nd:GdLuCOB) single crystal. An uncoated, 6.0-mm long, ZX-cut Nd:GdLuCOB medium yielded laser pulses with 1.76 W peak power for absorbed pump pulses of 5.49 W peak power, corresponding to an overall optical-to-optical efficiency ηoa = 0.32; the slope efficiency was ηsa = 0.44. Comparison is made with an uncoated XY-cut Nd:GdCOB medium (4.0-at.% Nd doping and 6.8-mm length) from which laser pulses with 1.74 W peak power (at optical efficiency ηoa = 0.25) and 0.31 slope efficiency were obtained. The improvements in laser emission of Nd:GdLuCOB at the fundamental wavelength are important for future self-frequency doubling in ZX principal plane of this crystal.