Growth, thermal and spectral properties, and laser performance of Tm:CNGS crystal

New composite functional crystals of Tm 3+ :Ca 3 NbGa 3 Si 2 O 14 (Tm 3+ :CNGS) were successfully grown by the Czochralski (CZ) method. The structural, thermal and spectral properties of Tm 3+ :CNGS crystals were investigated. The laser output of a Tm 3+ :CNGS crystal in the 2 μm band was studied for the first time. The results showed that Tm 3+ :CNGS achieved a maximum output of 740 mW at a pump power of 5 W, and the slope efficiency and light-to-light conversion efficiency reached 17.07% and 14%, respectively. The thermal properties are presented, and the coefficient of linear thermal expansion of Tm 3+ :CNGS increased with respect to that of a pure CNGS crystal in the Z -axis direction, which may have been due to a change in the bulk density of the oxygen dodecahedron in the X -axis direction after partial replacement of the rare earth ions. In addition, the specific heat, thermal diffusivity, and thermal conductivity of Tm 3+ :CNGS slightly increased in comparison with those of the undoped CNGS crystal. The absorption spectra of Tm 3+ :CNGS had a strong peak at 793 nm, and its absorption cross-section was 5.01 × 10 −21 cm 2 . The fluorescence spectra at room temperature had a full width at half maximum (FWHM) of 164 nm and a peak wavelength of 1888 nm, and the lifetime of the 3 F 4 upper energy level of the laser was 2.345 ms. Its good thermal properties, large emission linewidth, and ease of growth indicate that a Tm 3+ :CNGS single crystal could have the potential to be a good laser gain medium. High-quality crystals of Tm 3+ :CNGS were successfully grown by the Czochralski method. The laser performance of the trigonal crystal system at 2 μm is presented for the first time, and the structural, thermal, and spectral properties are also reported.