1.9 µm waveguide laser fabricated by ultrafast laser inscription in Tm:Lu₂O₃ ceramic

The ultrafast laser inscription technique has been used to fabricate channel waveguides in Tm³⁺-doped Lu₂O₃ ceramic gain medium for the first time to our knowledge. Laser operation has been demonstrated using a monolithic microchip cavity with a continuous-wave Ti:sapphire pump source at 796 nm. The maximum output power achieved from the Tm:Lu₂O₃ waveguide laser was 81 mW at 1942 nm. A maximum slope efficiency of 9.5% was measured with the laser thresholds observed to be in the range of 50-200 mW of absorbed pump power. Propagation losses for this waveguide structure are calculated to be 0.7 dB⋅cm^-1 ± 0.3 dB⋅cm^-1 at the lasing wavelength.