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Tm3+-doped CaY 0.9 Lu 0.1 AlO 4 single crystal was successfully grown by the Czochralski method. The crystal structure, polarized absorption spectra and polarized emission spectra of Tm:CaY 0.9 Lu 0.1 AlO 4 crystals were investigated. By using the Judd–Ofelt approach, the intensity parameters Ω 2,4,6 , spontaneous transition rate, branching ratios and radiative lifetimes were calculated. Diode-end-pumped continuous-wave Tm:CaY 0.9 Lu 0.1 AlO 4 lasers have also been investigated by establishing a simple and compact plane-concave cavity with four differently coated output couplers. Four different lasing wavelengths at about 2029 nm, 2000 nm, 1966 nm and 1888 nm have been achieved with maximum output power and slope efficiency of (1.98 W, 15.1%), (5.89 W, 46.2%), (6.92 W, 54.9%) and (5.54 W, 44.7%), respectively. The results in regard to the broad emission spectra and good laser performance show that the Tm:CaY 0.9 Lu 0.1 AlO 4 mixed crystal could be very promising for broadband tunable and/or femtosecond ultrafast laser generation in the important 2-μm spectral region. • Tm:CaY 0.9 Lu 0.1 AlO 4 crystal was grown by the Czochralski method. • The crystal structure, polarized spectra were investigated. • The maximum output power of 6.92 W with slope efficiency 54.9% was achieved. [ABSTRACT FROM AUTHOR]

Tm3+-doped calcium niobium gallium garnet (Tm:CNGG) single crystals have been successfully grown by the micro-pulling-down (μ-PD) method. The crystal structure, absorption spectra, fluorescence spectra and lifetimes of Tm:CNGG crystals were investigated. The absorption and emission bandwidths of Tm:CNGG crystals are larger than those of other Tm3+ doped garnet crystals, which will be beneficial for laser diode (LD) pumping and ultrashort pulse generation. Additionally, continuous wave (CW) laser operation around 2 μm was achieved in the 2.0 at.% Tm:CNGG crystal by LD pumping. [ABSTRACT FROM AUTHOR]

Abstract Eu3+-doped Bi 4 Ge 3 O 12 (BGO) single crystal with the size of Ø2 × 83 mm3 was successfully grown by the micro-pulling-down method. The absorption cross section, emission cross section and Judd–Ofelt analysis of Eu:Bi 4 Ge 3 O 12 (Eu:BGO) were reported for the first time. The absorption cross-section is 1.03 × 10−20 cm2 with full-width at half-maximum of 3.1 nm at around 393 nm. The spectroscopic intensity parameter Ω t (t = 2,4,6), radiative transition probabilities, branching ratios and radiative lifetime were obtained, respectively. Furthermore, the stimulated emission cross-section centered at 611 nm was calculated to be 6.32 × 10−21 cm2. The fluorescence lifetime of 5D 0 level was obtained to be 1.51 ms. The results indicate that Eu: BGO single crystal could be a potential laser host in the visible range. [ABSTRACT FROM AUTHOR]

Dy3+-doped Y 3 Al 5 O 12 (YAG) and Y 3 ScAl 4 O 12 (YSAG) single crystals have been successfully grown by the micro-pulling-down (μ-PD) technique for the first time. The room temperature absorption spectra, fluorescence spectra and fluorescence decay curves were measured. Dy:YAG and Dy:Y 3 ScAl 4 O 12 crystals exhibit strongest emission centered at 583 nm, corresponding to the 4F 9/2 → 6H 13/2 transition. The decay lifetime of the 4F 9/2 level was measured to be 634 μs and 667 μs, respectively. All these results indicate that the Dy:YAG and Dy:Y 3 ScAl 4 O 12 crystals are promising candidates for yellow laser operation. • Dy:YAG and Dy:YSAG crystals were grown by the micro-pulling-down method. • Dy:YAG and Dy:YSAG crystals exhibit strong emission centered at 583 nm. • Dy:YSAG crystal has a wide emission bandwidth due to the disordered crystalline structure. [ABSTRACT FROM AUTHOR]