Multiwatt, tunable, diode-pumped CWYb:GdCOB laser

We demonstrate that Yb-doped Ca4GdO(BO3)(3) (GdCOB) crystals are suitable for the development of high-power diode-pumped lasers emitting at around 1.041 mum. A 15%-doped Yb:GdCOB crystal was longitudinally pumped with a cw fiber-coupled diode emitting 10W at 976nm. While 5.2W of diode power was absorbed, we obtained 3.2W of 1043-mum laser light, with a beam quality factor M-2 equal to 3, and 2.5 W in a diffraction-limited beam. Furthermore, the laser is continuously tunable between 1018 and 1086 nm, Thermal effects have been investigated with a Shack-Hartmann wavefront analyser: although thermal lensing is not negligible, it does not affect the performance of the laser with the resonator design we used.