We report for the first time, to the best of our knowledge, on a diode-pumped passively $Q$-switched $\mathrm{Er},\mathrm{Yb}\text{:}{\mathrm{GdAl}}_3{({\mathrm{BO}}_3)}_4$ laser. By using a ${\mathrm{Co}}^{2+}\text{:}{\mathrm{MgAl}}_2{\mathrm{O}}_4$ crystal as a saturable absorber, $Q$-switched laser pulses with a duration of 12 ns and a maximum energy of 18.7 μJ at a repetition rate of 32 kHz corresponding to an average output power of 0.6 W were obtained at 1550 nm under continuous-wave pumping. In the burst mode of operation, $Q$-switched laser pulses with the highest energy up to 44 μJ were realized with a pulse repetition rate of 6.5 kHz.

We report the highly efficient continuous-wave diode-pumped laser operation of Er, ${\mathrm{Yb}\text{:}\mathrm{GdAl}}_3{({\mathrm{BO}}_3)}_4$ crystal. Absorption and stimulated emission spectra, emission lifetimes, and efficiencies of energy transfer from ${\mathrm{Yb}}^{3+}$ to ${\mathrm{Er}}^{3+}$ ions were determined. A maximal output power of 780 mW was obtained at 1531 nm at absorbed pump power of 4 W with slope efficiency of 26%.

We demonstrate a passively Q-switched Er,Yb:GdAl₃(BO₃)₄ diode-pumped laser emitting near 1.5 µm. By using a single-walled carbon nanotube (SWCNT) as a saturable absorber, Q-switched laser pulses with energy of 0.8 µJ and duration of 130 ns at a maximum repetition rate of 500 kHz were obtained at 1550 nm.

A transparent Er³⁺,Yb³⁺:GdMgB₅O₁₀ single crystal with dimensions up to 24 × 15 × 12 mm was grown successfully by the high-temperature solution growth on dipped seeds technique from K₂Mo₃O₁₀-based solvent. The grown crystal was characterized using PXRD, DSC and ATR techniques. Differential scanning calorimetry measurements and SEM analysis of the heat-treated solids revealed Er,Yb:GdMgB₅O₁₀ to be an incongruent melting compound with an onset point of 1087 °C. The absorption edge of the Er,Yb:GMBO sample is located in the region of 245 nm, which approximates a value of 4.8 eV. Absorption and emission spectra, and luminescence kinetics, were studied. The energy transfer efficiency from ytterbium to erbium ions was determined. The laser operation in continuous-wave mode was realized and output characteristics were measured. The maximal output power of 0.15 W with a slope efficiency of 11% was obtained at 1568 nm.

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.

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.