We have determined the growth charge composition and low thermal gradient (< 1°C/cm) Czochralski pulling parameters for the growth of bulk homogeneous Yb³⁺-doped NaBi(MoO₄)₂ crystals and assessed the main spectroscopic characteristics of the Yb³⁺:NaBi(MoO₄)₂ crystals as laser materials.

In this paper, Er:Y₂O₃ optical ceramics were fabricated and details of the synthesis were presented. The spectral–luminescent properties of Er³⁺:Y₂O₃ optical ceramics were investigated. The absorption and emission cross-section spectra were determined. The luminescence kinetics at near 1.6 µm was single exponential and the lifetime of erbium ⁴I_13/2 energy level was determined. In the frame of the conventional Judd–Ofelt theory, the emission properties of the energy levels of erbium ⁴I_13/2 and ⁴I_11/2 involved in laser operation at near 1.6 µm were calculated. The gain coefficient curves for typical values of the relative population of the upper laser level ⁴I_13/2 were presented. The composition and structure were studied using the SEM, XRD, FTIR spectroscopy, and X-ray computer tomography techniques.

A transparent Yb:YMgB₅O₁₀ single crystal with dimensions up to 25 × 23 × 25 mm and weight 10.337 g was grown using a high-temperature solution growth on dipped seeds technique with a K₂Mo₃O₁₀ solvent. The Yb³⁺ concentration was calculated to be 4.7 at.% (N_Yb = 3.71 × 10²⁰ atoms/cm³) with a distribution coefficient K_d of 0.59. The grown crystal was characterized by means of PXRD, TGA-DSC and ATR-FTIR techniques. The spectroscopic characteristics of the Yb:YMgB₅O₁₀ crystal were demonstrated. Absorption cross-section spectra were produced. The luminescence spectra of the Yb:YMgB₅O₁₀ crystal were measured in the spectral range of 950–1100 nm. The luminescence kinetics of the ²F_5/2 energy level were investigated and the lifetime was determined.

The growth, spectroscopy and lasing performance of a Tm,Ho:KY(WO⁴)²crystal are reported. An average power up to 390mW is generated at 2058nm with a corresponding slope efficiency of 42% during continuous-wave operation at room temperature.