Femtosecond mode-locking of epitaxially grown Yb:KLu(WO/sub 4/)/sub 2/ composites

Epitaxial growth of highly Yb-doped films on passive substrates is especially interesting for the strongly anisotropic monoclinic double tungstate hosts where the extremely large cross sections would permit the utilization of the thin disk laser concept with very thin (<100 /spl mu/m) active layers which can be face cooled and pumped in a single pass. In this paper femtosecond mode-locked operation with the same 10% Yb-doped KLuW/KLuW sample is demonstrated. The 100-/spl mu/m thick Yb:KLuW layer was grown by liquid phase epitaxy on the [010] face, normal to the N/sub p/-principal optical axis, of a 1.1-mm thick KLuW substrate.