Watt-level europium laser at 703 nm

We report on a watt-level highly efficient europium laser operating at the ${^5{\rm D}_0 \to {^7}{\rm F}_4}$ transition. It is based on the stoichiometric ${\rm KEu}{({\rm WO}_4)_2}$ crystal. Under pumping by a green laser at 532.1 nm, the ${\rm KEu}{({\rm WO}_4)_2}$ laser generated a maximum peak output power of 1.11 W at ${\sim}{703}\;{\rm nm}$ with a slope efficiency of 43.2% and a linear polarization ($E\|\;{N_m}$). A laser threshold as low as 64 mW was achieved. True continuous-wave operation was demonstrated. The polarized emission properties of monoclinic ${\rm KEu}{({\rm WO}_4)_2}$ were determined.