Yb3+: KGd(WO4)2 (Yb:KGW) is one of the most promising laser active materials. Yb:KGW crystal is expected to replace Nd:YAG crystal and Yb:YAG crystal in high power diode pumped laser system. Yb:KGW also has great potential for high power, short pulse time femtosecond lasers and their wide application.
Yb3+:KGW has large absorption coefficient, low quantum defect, high absorption and emission cross section
The simple two-level electronic structure of the Yb ion avoids undesired loss processes such as upconversion, excited state absorption, and concentration quenching. Compared to the commonly used Nd:YAG crystal, Yb:KGW crystal has a much larger absorption bandwidth, 3 or 4 times longer emission lifetime in similar hosts with enhanced storage capacity, lower quantum defect and is more suitable for diode pumping than the traditional Nd-doped systems. The smaller Stokes shift reduces heating and increases the laser efficiency. In comparison with other Yb doped laser crystals such as Yb:YAG and Yb:YCOB crystals, Yb:KGW has a much higher (13-17 times) cross-section of absorption, lower quantum defect (~4%), a cross-section of emission that is 9 times higher than Yb: YCOB, and an emission band that is broader than Yb:YAG, a high nonlinear coefficient of refraction, and the highest slope efficiency (87%).