Spectroscopy and high-power laser operation of a monoclinic Yb³⁺:MgWO₄ crystal

Monoclinic (wolframite-type) monotungstate crystals are promising for rare-earth doping. We report polarized room- and low-temperature spectroscopy and efficient high-power laser operation of such a ${{\rm Yb}^{3 + }}{:}\,{{\rm MgWO}_4}$Yb³⁺:MgWO₄ crystal featuring high stimulated emission cross section (${\sigma _{\rm SE}}\; = \;{6}.{2}\; \times \;{{10}^{ - 20}}\;{{\rm cm}^2}$σ_SE=6.2×10^-20cm² at 1056.7 nm for light polarization ${\rm E}\;||\;{N_m}$E||N_m), large Stark splitting of the ground state (${765}\;{{\rm cm}^{ - 1}}$765cm^-1), large gain bandwidth (26.1 nm for ${\rm E}\;||\;{N_g}$E||N_g), and strong Raman response (most intense mode at ${916}\;{{\rm cm}^{ - 1}}$916cm^-1). A diode-pumped ${{\rm Yb}^{3 + }}{:}\,{{\rm MgWO}_4}$Yb³⁺:MgWO₄ laser generated 18.2 W at ${\sim}{1056}\;{\rm nm}$∼1056nm with a slope efficiency of ${\sim}{89}\% $∼89% and a linearly polarized laser output.