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Abstract Nd3+-doped Bi 4 Ge 3 O 12 (Nd:BGO) single crystals have been successfully grown by the micro-pulling-down (μ-PD) method. The absorption spectra, fluorescence spectra and fluorescence decay curve have been measured at room temperature. The absorption cross section is about 1.39 × 10–20 cm2 at around 808 nm for 0.3 at% Nd:BGO. The Judd–Ofelt theory has been applied to calculate the intensity parameters, and three spectroscopic parameter Ω t (t = 2,4,6), radiative transition probabilities, radiative lifetime and branching ratios were calculated. The stimulated emission cross-section of 4F 3/2 →4I 11/2 transition at 1064 nm was obtained to be 3.29 × 10–20 cm2 for 0.3 at% Nd3+-doped BGO crystal. The fluorescence lifetimes of 0.3 at% and 1.0 at% neodymium-doped BGO crystals were measured to be 288 μs and 242 μs, respectively. Those results indicate that Nd3+-doped BGO crystal grown by the μ-PD method would be a potential laser medium. [ABSTRACT FROM AUTHOR]

Pr 3+ -doped YAlO 3 (YAP) single crystal was successfully grown by the Czochralski (Cz) method. Polarized absorption and polarized fluorescence spectra were measured at the room temperature. The spectroscopic parameters based on the polarized absorption spectra were calculated by Judd-Ofelt (J-O) theory for the first time. The fluorescence lifetime of 3 P 0 energy level was fitted to be 19.16 μs with the quantum efficiency of 95.8%. Through the analyzing of the spectroscopic properties, Pr:YAP crystal was demonstrated to be a promising candidate for solid state laser operation. [ABSTRACT FROM AUTHOR]

In this paper, the Floating zone technique was used to grow high-quality Cr3+:YScO 3 crystals. The absorption cross-sections of the 4A 2 →4T 1 transition and 4A 2 →4T 2 transitions were calculated to be 1.71 × 10−20 cm2 at 488 nm and 0.72 × 10−20 cm2 at 666 nm, respectively. The crystal field strength Dq, Racah parameters B, and C were calculated to be 1502 cm−1, 533 cm−1, and 3362 cm−1, respectively. In the Cr3+:YScO 3 crystal, the effective phonon energy and Huang-Rhys factor S were calculated to be 284 cm−1 and 8.62, respectively. The emission cross-section at 988 nm corresponding to the 4T 2 →4A 2 transition was calculated to be 1.44 × 10−20 cm2 with full width at half maximum (FWHM) of 318 nm. All the results show that Cr3+:YScO 3 crystal has the potential to be a tunable and ultrafast laser crystal. • Cr:YScO 3 crystals were successfully grown by the Floating zone technique(FZ) method. • Broad emission spectrum with full width at half maximum (FWHM) of 318 nm in Cr:YScO 3 crystals was observed. • Spectral properties and crystal field parameters of Cr:YScO 3 crystals were investigated and analysed. [ABSTRACT FROM AUTHOR]

Ho3+-doped CaY 0.9 Gd 0.1 AlO 4 single crystal was successfully grown by the Czochralski technique for the first time. The polarized absorption spectra, polarized luminescence spectra and fluorescence decay curve of the crystal were investigated at room temperature. The spectroscopic parameters are calculated based on Judd–Ofelt theory, the values of Ω 2,4,6 were calculated to be 3.16 × 10−20 cm2, 3.93 × 10−20 cm2, 0.91 × 10−20 cm2, respectively. The Ho:CaY 0.9 Gd 0.1 AlO 4 crystal exhibits strong emission at 2013 nm for π- and 2032 nm for σ-polarizations with stimulated emission cross section of 6.64 × 10−20 cm2 and 1.90 × 10−20 cm2, respectively. The fluorescence lifetime of the 5I 7 level was measured to be 6.60 ms. The continuous-wave (CW) laser operation of Ho:CaY 0.9 Gd 0.1 AlO 4 crystal around 2 μm was demonstrated. • Ho3+-doped CaY 0.9 Gd 0.1 AlO 4 single crystal was successfully grown by the Czochralski technique for the first time. • The emission cross-section at 2013 nm and 2032 nm are 6.64 × 10−20 cm2 and 1.90 × 10−20 cm2 for π- and σ-polarizations respectively. • The continuous-wave (CW) laser operation of Ho:CaY 0.9 Gd 0.1 AlO 4 crystal around 2 μm was demonstrated. [ABSTRACT FROM AUTHOR]

Ho3+ and Eu3+ co-doping GdScO 3 crystal was successfully grown by special EFG method. The spectroscopic properties of the crystal were measured and analyzed. The absorption cross section was calculated to be 2.027 × 10−20 cm2 at 1161 nm. The J-O theory intensity parameters Ω t (t = 2, 4, 6), radiative transition rates, fluorescence branching ratios and radiative lifetimes were calculated. The Ho,Eu:GdScO 3 crystal has very strong emission at 2869 nm and the emission cross section was 13.524 × 10−21 cm2. The fluorescence lifetimes of the 5I 7 and 5I 6 levels were measured to be 4.457 ms and 1.265 ms. Confirmed that Eu3+ can be used as an effective deactivation ion of Ho3+ in GdScO 3 crystal. All those results show that the Ho,Eu:GdScO 3 crystal would be a potential laser material for ∼3 μm mid-infrared region. • Ho,Eu:GdScO 3 crystal was successfully grown. • The spectroscopic properties of the Ho,Eu:GdScO 3 crystal were analyzed. • J-O theory was applied to analyze fluorescence properties of the Ho,Eu:GdScO 3 crystal. • The energy transfer between Ho3+ and Eu3+ ions, spectroscopic characteristic of ∼3 μm emission were calculated and analyzed. [ABSTRACT FROM AUTHOR]

Ho:Lu 2 O 3 crystal was successfully grown by TGT method. The spectroscopic properties of the crystal were analyzed. The absorption cross section of Ho:Lu 2 O 3 were 0.307 × 10−20 cm2 at 1147 nm and 1.076 × 10−20 cm2 at 1929 nm. J-O theory was applied to analyze fluorescence properties of the Ho:Lu 2 O 3 crystal. The intensity parameters Ω t (t = 2,4,6), radiative transition rates, branching ratios and radiative lifetime were calculated. The Ho:Lu 2 O 3 crystal had very strong emission at 2027 nm and 2849 nm and emission cross sections were calculated to be 3.271 × 10−21 cm2 and 8.852 × 10−21 cm2, respectively. The fluorescence lifetimes of the Ho3+5I 7 and 5I 6 levels were measured to be 12.400 ms and 0.622 ms. All those results show that the Ho: Lu 2 O 3 crystal would be a potential laser material for mid-infrared region. • Ho: Lu 2 O 3 crystal was successfully grown by TGT method. • The spectroscopic properties of the Ho: Lu 2 O 3 crystal were analyzed. • J-O theory was applied to analyze fluorescence properties of the Ho:Lu 2 O 3 crystal. • The gain cross-section of Ho:Lu 2 O 3 crystal for ∼2 μm region and ∼3 μm region were calculated. [ABSTRACT FROM AUTHOR]

Abstract: Praseodymium and cerium co-doped yttrium silicate (Pr,Ce:YSO) crystal with high optical quality was grown by the Czochralski method. The segregation coefficient of Pr3+ and Ce3+ is measured to be 0.547 and 0.136, respectively. The polarized absorption bands centered at 268nm, 299nm and 356nm were assigned to 4f (2F5/2)→5d inter-configuration transitions of Ce3+, while bands centered at 220nm and 250nm were assigned to 4fn–4fn−15d transitions of Pr3+. The VUV–UV excitation spectra for monitoring Pr3+ emissions centered at 610nm (1D2→3H4) and 489nm (3P0→3H4), as well as Ce3+ emission centered at 450nm were recorded at T=8K in the range of 100nm–320nm. Polarized excitation spectra for Ce3+ emission centered at 424nm and Pr3+ emission centered at 611nm were recorded at T=300K. Polarized emission spectra were obtained upon excitation at 365nm and 456nm at T=300K. Lifetimes were estimated to be 170μs for Pr3+ (1D2), 3μs for Pr3+ (3P0) and 39ns for Ce3+ (5d1). [Copyright &y& Elsevier]

Ho3+-doped GdScO 3 crystal was successfully grown by the edge-defined film-fed growth (EFG) method. The spectroscopic properties of Ho:GdScO 3 crystal were investigated at room temperature. The peak absorption cross-sections were 0.33 × 10−20 cm2 and 1.24 × 10−20 cm2 at 1160 nm and 653 nm with full widths at half maximum of 171.7 nm and 11.5 nm. The peak emission cross-sections of 5I 7 →5I 8 and 5I 6 →5I 7 transitions for the crystal were 0.49 × 10−20 cm2 and 1.24 × 10−20 cm2, respectively. The fluorescence lifetimes of the 5I 6 and 5I 7 multiplets were measured to be 1.12 ms and 6.13 ms, respectively. The results show that Ho:GdScO 3 crystal is a very promising material for 3 μm laser operation. • Ho:GdScO 3 crystal was successfully grown by the edge-defined film-fed growth (EFG) method. • The structure parameters of Ho:GdScO 3 crystal were studied by X-ray diffraction (XRD). • Spectral properties and Judd-Ofelt parameters of Ho:GdScO 3 crystal were investigated and compared. [ABSTRACT FROM AUTHOR]

GdScO 3 single crystal codoped with Tm3+ and Tb3+ ions was successfully grown by the Edge-defined Film-fed Growth Method (EFG) for the first time. Absorption, fluorescence spectrum and fluorescence lifetimes of the grown crystal at room temperature were measured. The absorption cross-section at 789 nm was calculated to be 8.20 × 10−21 cm2. The emission cross-section was 1.35 × 10−21 cm2 at 1504 nm with the FWHM of 95.3 nm. The fluorescence lifetimes of the 3H 4 state and the 3F 4 state were fitted to be 253 μs and 1460 μs, respectively. Compared with Tm3+ single doped GdScO 3 crystal, the codoping of Tb3+ successfully depopulated the 3F 4 energy level and enhanced the emission at 1.5 μm region. It indicated that Tm,Tb:GdScO 3 could be favorable laser medium for 1.5 μm-laser operation. • Tm3+ and Tb3+ co-doped GdScO 3 crystal was successfully grown by the edge-defined film-fed method (EFG) for the first time. • Spectral parameters and Judd-Ofelt parameters of Tm,Tb:GdScO3 crystal were obtained and compared. • The fluorescence mechanism of Tm3+ and Tb3+ co-doped GdScO 3 crystal has been studied. [ABSTRACT FROM AUTHOR]

LaMgAl 11 O 19 (LMA) crystal with nominal Sm3+ concentrations of 8 at.% was grown by the Czochralski method. Polarized absorption spectra, polarized emission spectra and fluorescence decay curve of Sm:LMA crystal were recorded at room temperature. The absorption cross-sections at 404 nm were calculated to be 2.33 × 10−20 cm2 and 0.86 × 10−20 cm2 for σ and π polarization, respectively. The spontaneous transition rates, branching ratios and the radiative lifetime of the 4G 5/2 multiplet, were calculated. The Judd-Ofelt theory has been applied to evaluate the Ω t (t = 2, 4, 6) intensity parameters. The highest stimulated emission cross-sections for the 4G 5/2 → 6H 7/2 transition around 594 nm were calculated to be 1.67 × 10−21 cm2 for σ polarization and 1.15 × 10−21 cm2 for π polarization, with full width at half maximum (FWHM) of 7.68 nm and 7.27 nm, respectively. The fluorescence lifetime of the 4G 5/2 manifold was 1.84 ms. All the results show that Sm:LMA crystal would be a promising orange-red solid state laser material. • The most intensive absorption line of Sm3+ ion, suitable for 405 nm InGaN laser diode. • The rigidity of Sm:LMA crystal is higher than some host crystals. • The value Ω 2 of Sm:LMA crystal is comparable to Sm:LiYF 4. • The large parameter σ em τ of Sm3+ in LMA is beneficial for the solid state laser. [ABSTRACT FROM AUTHOR]