A continuous wave Yb:KGW laser with polarization-independent pump absorption

A polarization-independent pumping scheme for an end-pumped Yb:KGd(WO4)2 laser oscillator is proposed. It enables the use of compact, high power and high brightness fiber-coupled laser diode modules as pump sources and results in reduced thermal effects, good beam quality and improved output power stability. Based on this design, a continuous wave Yb:KGW laser with polarization-independent pump scheme is demonstrated. The laser delivered 2 W of average output power in TEM00 mode at 1040 nm. The induced thermal lens is reduced by a factor of 2 when compared to conventional diode pumping schemes, which clearly demonstrates the potential of the geometry of this crystal for power scaling.