CaF2:Yb laser ceramics

[Display omitted] ► Hot-pressing technique produced CaF2:Yb ceramics with superior mechanical properties. ► For the first time, lasing has been observed for the hot-pressed CaF2:Yb ceramics. ► Сa0.95Yb0.05F2.05 ceramics has exhibited ηsl=35% for the pulse-periodic conditions. ► Сa0.97Yb0.03F2.03 sample has exhibited ηsl=30% under both pulse and CW conditions. ► Thermal conductivity increases with decreasing of YbF3 content in CaF2:Yb ceramics. CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical properties as starting single crystals. Slope efficiency of the Сa0.95Yb0.05F2.05 is equal to 35% in the pulsed mode of laser operation. Decrease of ytterbium concentration in CaF2:Yb samples down to 3mol.% resulted in the essential improvement of Сa0.97Yb0.03F2.03 thermal conductivity from 3.5 to 4.5W/mK, but slightly decreased (down to 30%) slope efficiency of the samples under both pulsed and CW mode of operation. Alternative hot-pressing synthesis of CaF2:Yb fluoride laser ceramics provided materials with superior mechanical properties (microhardness Н=3.2GPa and fracture toughness К1С=0.65МPаm1/2) in comparison with hot-formed and/or single crystal CaF2:Yb specimens. For the first time, lasing has been observed for the novel aforementioned hot-pressed CaF2:Yb ceramics.