Abstract

Previous works on Ytterbium-doped alcaline-earth fluoride have impressively shown that these materials are suitable for high-peak power operation [1,2] due to their broad emission spectrum comparable with rare-earth doped laser glasses. From the scaling point of view Yb:CaF₂ is the most promising material since crystal growth at large sizes with diameters up to 100 mm and more with high optical quality have been demonstrated so far. Also the thermo-mechanical and thermo-optical properties such as the negative thermal lens of Yb:CaF₂ are superior for high-average power lasers [3]. Moreover, the high saturation fluence (i.e. 80 J/cm²) pushes the potential energy limit of thin disk lasers by about one order of magnitude compared to oxide laser materials such as Yb:YAG. This means that at a given stored energy parasitic lasing is reduced by a low transverse gain [4]. However, the low single-pass gain of Yb:CaF₂ lasers must compensated by a large number of amplifier passes.

© 2011 Optical Society of America