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The crystal growth, optical spectra and lifetime of Dy:CaGdAlO 4 crystal were investigated for the first time to our best knowledge. Single Dy:CaGdAlO 4 crystal with size of Φ4 × 40 mm 3 was grown by floating zone method. The peak absorption cross-sections were calculated to be 2.43 × 10 −21 cm 2 and 1.28 × 10 −21 cm 2 at 453 nm for σ and π polarizations. The Judd-Ofelt (JO) parameters of Ω 2 , Ω 4 and Ω 6 were calculated to be 1.8 × 10 −20 cm 2 , 1.0 × 10 −20 cm 2 and 0.5 × 10 −20 cm 2 , respectively. The emission cross-sections were calculated to be 0.51 × 10 −20 cm 2 and 0.55 × 10 −20 cm 2 for σ and π polarizations. The fluorescence decay time is 222 μs. The results indicate that the Dy:CaGdAlO 4 crystal is a potential candidate for yellow laser operation. [ABSTRACT FROM AUTHOR]

Sm:YAlO 3 (Sm:YAP) crystal with size of Φ28 × 80 mm3 was grown by Czochralski (Cz) method. Polarized absorption spectra and fluorescence spectra of Sm:YAP crystal were discussed for the first time. The peak emission cross-sections were calculated to be 0.80 × 10−21 cm2 (604 nm for a-polarization), 1.82 × 10−21 cm2 (604 nm for b-polarization) and 1.63 × 10−21 cm2 (610 nm for c-polarization), respectively. The Judd-Ofelt (JO) intensity parameters were calculated to be Ω 2 = 2.59 × 10−20 cm2, Ω 4 = 1.78 × 10−20 cm2 and Ω 6 = 2.98 × 10−20 cm2, respectively. The decay lifetime of 4G 5/2 energy level was measured to be 2.51 ms. All above results indicate the Sm:YAP crystal may be a potential candidate of reddish-orange laser pumped directly by the GaN/InGaN laser diode. • Sm:YAlO 3 crystal was grown by Cz method. • Polarized optical spectra of Sm:YAlO 3 crystal were investigated. • The transitions of 4G 5/2 → 6H 7/2 have the highest branching ratio value, which is suitable for reddish-orange laser. [ABSTRACT FROM AUTHOR]

High quality Pr3+ single-doped PbF 2 and Pr3+/Yb3+ co-doped PbF 2 single crystals were grown by temperature gradient technique (TGT). By co-doping Yb3+ ion as Pr3+ ions sensitizer, the visible light emission can be regulated and the largest luminescence branching ratio can be switched from red-orange to blue-green light. Besides, when Pr3+ ions doping concentration is as low as possible, the blue light self-absorption effect can be weakened, which is beneficial to high-efficiency blue laser output. Moreover, the broad band emission around 1.3 μm from 1G 4 energy level can be observed in the Pr3+/Yb3+:PbF 2 crystal with the low maximum phonon energy for the first time. Absorption, emission spectra and luminescence mechanism are well analyzed by the energy transfer process and J-O theory. The laser upper energy level lifetime of Pr3+ ions has a great increase by Yb3+ ion effect. These advantageous spectroscopic characteristics show that the Pr3+/Yb3+:PbF 2 crystal might be potential laser gain materials for blue-green and ∼1.3 μm near-IR laser operation. • By co-doping Yb3+ ion as sensitizer for Pr3+ ions, the visible light emission can be regulated and the largest luminescence component ratio can be changed from red-orange light to blue-green light. • When doping concentration of Pr3+ ion is as low as possible, the self-absorption effect of blue light can be weakened, which is beneficial to high-efficiency blue laser output. • The broad band emission around 1.3 μm from 1G 4 energy level can be observed in the Pr3+/Yb3+: PbF 2 crystal with the low maximum phonon energy for the first time. [ABSTRACT FROM AUTHOR]

Titanium doped sapphire (Ti:Al 2 O 3 ) crystal fibers have been grown by the micro-pulling-down (μ-PD) method using different pulling rate in the range (0.1–0.5 mm/min). The present work has investigated the crystal growth, including diameter, bubbles defects and segregation properties. The fiber’s absorption and IR emission experiments are analyzed. The lifetime of Ti 3+ in the IR range obtained at room temperature is 3.1 μs. Moreover, the two blue emissions at 420 nm and 470 nm bands have been discussed. [ABSTRACT FROM AUTHOR]

Tm3+ doped and Tm3+, Pr3+ co-doped Lu 3 Al 5 O 12 (LuAG) garnet single crystals have been successfully grown by the micro-pulling-down (μ-PD) method. The absorption spectra, fluorescence spectra and lifetimes were investigated at room temperature. In the absorption spectra, the transition centered at 782 nm matches well with the GaAlAs LDs laser pumping. The incorporation of Pr3+ into Tm3+-doped LuAG crystals enhanced the intensity of 1.5 μm emission and decreased the fluorescence lifetime of the lower energy level for 1.5 μm emission from 10.427 ms to 2.603 ms. The results indicate that Tm,Pr:LuAG crystal can be promising candidate for near infrared 1.5 μm laser materials. • Tm:LuAG and Tm,Pr:LuAG crystals have been successfully grown by the micro-pulling-down (μ-PD) method. • Spectral parameters of Tm:LuAG and Tm,Pr:LuAG crystals were obtained and compared. • The fluorescence mechanism of Tm,Pr:LuAG crystal has been studied for the first time. [ABSTRACT FROM AUTHOR]

Tm3+- doped GdScO 3 single crystal was successfully grown by the edge-defined film-fed method (EFG) for the first time. The spectroscopic properties of the crystal were investigated at room temperature. The absorption cross section of Tm:GdScO 3 at 795 nm is 1.58 × 10−20 cm2. By applying the Judd–Ofelt approach, the intensity parameters Ω 2,4,6 , radiative transition rates, branching ratios and radiative lifetime were calculated. Tm:GdScO 3 exhibits strong emission at 1460 nm and 2300 nm with stimulated emission cross section of 1.8 × 10−21 cm2 and 2.7 × 10−21 cm2, respectively. The fluorescence lifetime of the 3H 4 level was measured to be 265 μs. All the results indicated that the Tm:GdScO 3 crystal is a potential laser material. • Tm:GdScO 3 crystal was successfully grown by the edge-defined film-fed method (EFG) for the first time. • The structure parameters of Tm:GdScO 3 crystal were investigated by XRD. • Spectral parameters and Judd-Ofelt parameters of Tm:GdScO 3 crystal were obtained and compared. [ABSTRACT FROM AUTHOR]

High quality of Tb3+-single doped and Tb3+/Pr3+ co-doped CaF 2 crystals were grown by the temperature gradient technique (TGT). Pr3+ ions were used as sensitizing ions of Tb3+. Optical properties including absorption spectrum, emission spectrum, and fluorescence decay curve were recorded. Through co-doping sensitizing ions of Pr3+, the absorption cross section around 480 nm increased from 0.007 × 10−20 cm2 to 0.3 × 10−20 cm2, the large value is beneficial for the absorption of LD pump source. Judd-Ofelt theory was used to analyze the spectroscopic parameters. Fluorescence branch ratio, transition probability, radiative and fluorescence lifetimes, and quantum efficiency were determined as well. The emission cross section of Tb,Pr:CaF 2 for the green emission at 544 nm and yellow emission at 587 nm corresponding to the transition of 5D 4 →7F 5 and 5D 4 →7F 4 were calculated to be 5.56 × 10−22 cm2 and 8.78 × 10−23 cm2, respectively, which is comparable to the Tb3+ doped CaF 2 crystal. • Tb:CaF 2 crystal and Tb/Pr co-doped CaF 2 crystal were grown by TGT method. • Pr3+ ions were used to improve the absorption cross section of Tb3+ ions. • Judd-Ofelt theory was used to analyze the spectroscopic parameters. • Tb,Pr:CaF 2 crystal is a potential laser material for green and yellow oscillation. [ABSTRACT FROM AUTHOR]

Tb3+ doped Y 3 Al 5 O 12 (Tb:YAG) single crystal has been grown by the Czochralski method. Optical spectroscopic characterization of the crystal was performed in order to evaluate the potential for the visible laser application. Based on the Judd–Ofelt theory, the spectroscopic parameters Ω t (t = 2, 3, 6), spontaneous transition probabilities, fluorescence branch ratio and the radiation lifetime of excited state 5D 4 state were calculated. The green emission cross section of 5D 4 →7F 5 transition were calculated to be 1.23 × 10−21 cm2 , The yellow emission cross section of 5D 4 →7F 4 transition were calculated to be 7.08 × 10−23 cm2. The decay time of the 5D 4 level was measured to be 3.12 ms, which is in reasonable agreement with the radiation lifetime of 3.30 ms. All the results indicate the potential of Tb:YAG crystal as a visible laser material. • Tb:YAG crystal was grown by Czochralski method. • Judd-Ofelt theory was used to analyze the spectroscopic properties of Tb:YAG for the first time. • Tb:YAG crystal is a potential laser material for yellow and green laser output. [ABSTRACT FROM AUTHOR]

Nd3+ doped Y 3 Sc x Al 5-x O 12 (x = 0.05, 0.5, 1) single crystals were successfully grown by the micro-pulling-down (μ-PD) technique. The effect of compositional parameter x on the structure, absorption, emission and fluorescence lifetime of Nd:Y 3 Sc x Al 5-x O 12 crystals was studied. The Nd3+ concentration in the core increased with increasing of compositional parameter x. The full width at half maximum (FWHM) of the emission band centered at 1064 nm was calculated to be 6.1, 7.1, and 7.3 nm for x = 0.05, 0.5 and 1, respectively. The fluorescence lifetimes of 4F 3/2 levels are 259.3, 269.6, and 276.9 μs for x = 0.05, 0.5, and 1, respectively. The results indicate that the Nd:Y 3 Sc x Al 5-x O 12 crystals are promising materials for laser output. • Nd:Y 3 Sc x Al 5-x O 12 crystals were successfully grown by the micro-pulling-down technique. • Spectral parameters of Nd:Y 3 Sc x Al 5-x O 12 crystals were obtained. • The effect of composition on the structure and spectral parameters was discussed. [ABSTRACT FROM AUTHOR]

High optical quality Er3+ doped Lu 2 O 3 single crystal with optimum doping concentration was grown by Floating zone (Fz) method. The spectral properties and Judd-Ofelt (JO) analysis were reported. The emission cross-section at 2772 nm was calculated to be 2.47 × 10−20 cm2 with FWHM of 188 nm. The fluorescence lifetime of 4I 11/2 and 4I 13/2 energy level was fitted to be 1.62 ms and 4.02 ms. Optimum lifetime ratio (τ low /τ up) is beneficial to laser operation. Compared with reported Er3+ doped crystal, the larger spectral quality factors Q and low inversion ratio P of 7 at.% Er:Lu 2 O 3 crystal indicate that it has a favorable laser performance for 2.8 μm laser operation. • In our work high optical quality 7 at.% Er3+ doped Lu 2 O 3 single crystal with optimum doping concentration was grown by Floating zone method. • The spectroscopic properties were reported by Judd-Ofelt theory. • In order to weaken the influence of reabsorption phenomenon, we grind sample of Er:Lu 2 O 3 crystal into powder to measure fluorescence lifetime of 4I 13/2. • The measured fluorescence lifetime of 4I 13/2 is close to actual value. • We compare the optical characteristics of 7at.% Er:Lu 2 O 3 crystal with other materials in Mid-infrared. [ABSTRACT FROM AUTHOR]