Free-running performance of Yb0.14:Y0.77Gd0.09Ca4O(BO3)3 mixed crystal laser operating around 1084 nm

Highly efficient high-power laser operation around 1084 nm is demonstrated of the Yb0.14:Y0.77Gd0.09Ca4O(BO3)3 mixed crystal in a compact plano-concave resonator, producing an output power of 18.1 W in free-running mode, with optical-to-optical and slope efficiencies being, respectively, 60% and 70% with respect to incident pump power. In laser action achieved with the high-gain short-wavelength oscillation being suppressed, the highest output power reaches 16.2 W with an optical-to-optical efficiency of 50.3%, while the slope efficiency amounts to 58%. The results presented reveal the superiority of the Yb-ion doped mixed oxyborate crystal to the existing Yb-ion or Nd-ion crystals capable of generating high-power laser radiation around 1084 nm.