Broadly tunable and low-quantum-defect Yb³⁺-doped double tungstate channel waveguide lasers

摘要

The potassium double tungstates are excellent candidates for solid-state lasers. These advantages have been exploited to demonstrate thin-disk lasers, broadly tunable and high-energy ultrashort-pulse lasers, low-quantum-defect lasers, as well as waveguide lasers [1]. Co-doping of grown KY(WO4)2:RE thin films with Gd and Lu ions for lattice matching and enhanced refractive index contrast [2] with respect to the undoped KY(WO4)2 substrate has enabled microstructured waveguide lasers [3] with tight pump and laser mode confinement of ∼10 µm², resulting in slope efficiencies in Yb-doped waveguides of 71% and 418 mW output power at 1023 nm [4].