Diode-pumped 1-W continuous-wave Er:YAG 3-mum laser

We have demonstrated 1.15 W of Gaussianlike (M(2) = 2) cw output at 2.94 mum from a diode laser end-pumped monolithic laser crystal composed of Er-doped yttrium aluminum garnet (YAG) bonded to undoped YAG. The laser was pumped with two polarization-coupled 2.5-W flared laser diodes that provided a 45-mum pump waist with a low N.A. (<0.04) . Output at 2.94 mum was generated with a 34% slope efficiency and a greater-than-unity quantum efficiency.