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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]

Highlights: [•] Spectroscopic properties and crystal growth of Tm:LYSO single crystal were studied for the first time. [•] The large absorption and emission cross-section and broad FWHM make Tm:LYSO a promising media for tunable and ultrashort pulses. [•] The J–O parameters and gain spectra reveal that the excellent properties for laser applications. [Copyright &y& Elsevier]

Abstract: Pr3+, Yb3+ co-doped CaYAlO4 (Pr, Yb: CYA) single crystal was grown using the Czochralski (CZ) method. For near-infrared quantum-cutting system, a quantum efficiency of 145% for Pr3+, Yb3+-codoped CYA crystal has been obtained by ignoring the nonradiative losses. Under excitation at 940nm, high intensities of 502nm, 555nm, 628nm, 661nm and 729nm emissions turn up. Fluorescence decay time of 3P0→3F2 emission of Pr3+ ions and 2F5/2→2F7/2 transition of Yb3+ ions were also studied as evidences for energy transfer. [Copyright &y& Elsevier]

Abstract: Sm:CaNb2O6 single crystal has been grown by the Czochralski method. Its high-temperature X-ray powder diffraction, optical absorption, emission spectroscopic as well as lifetime have been studied. Thermal expansion coefficients (α), J–O parameters (Ω i ), radiative lifetime (τ rad), branching ratios (β) and stimulated emission cross-sections (σ e) were calculated. The quantum efficiency (η) was calculated to be 97%. The intense peak emission cross section at 610, 658nm were calculated to be 2.40×10−21, 2.42×10−21 cm2. These results indicate that Sm:CaNb2O6 crystal has potential use in visible laser and photonic devices area. [Copyright &y& Elsevier]

Abstract: Crystals of Ce3+-doped (Lu x Y1−x )3Al5O12 (LuYAG) have been grown and studied by X-ray powder diffraction, emission spectroscopy, excitation spectroscopy and X-ray excited fluorescence spectroscopy. The X-ray powder diffraction pattern revealed that the as-grown LuYAG:Ce crystal possessed the garnet structure. Compared with Ce3+-doped Y3Al5O12 (YAG), the absorption bands associated with the 4f–5d transition shifted to shorter wavelengths, the emission band that originated from a transition from the lowest 5d level to the 2F ground state of the Ce3+ ions shifted to the blue, which was probably due to a larger Stokes shift of the emission, and the reduction of relative intensity of antisite defect emission in the X-ray excited fluorescence spectra revealed that introducing Lu ions into YAG could reduce the antisite defect. [Copyright &y& Elsevier]

The spectral properties of lightly doped Er:CaF 2 and Er,Pr:CaF 2 single crystals were investigated. Benefited from particular clustering effect, 2.79 μm continuous-wave (CW) laser operation was demonstrated in lightly doped 3 at.% Er:CaF 2 crystal. After co-doping small amount of Pr 3+ , the lifetime gap between Er 3+ : 4 I 11/2 and Er 3+ : 4 I 13/2 was shortened from 7.86 ms to about 1 ms. Moreover, the near-infrared and up-conversion fluorescence were significantly quenched. Thus, the CW laser performance was greatly improved. The slope efficiency was effectively improved from 8.0% to 15.8%. [ABSTRACT FROM AUTHOR]

A series of high quality x%Pr3+:BaF2 (x = 0.6, 1, 2); (1%Pr3+, 2%Na+):BaF2; (1%Pr3+, y%Ca2+):BaF2 (y = 3, 5) and (0.6%Pr3+, 10%R3+):BaF2 (R = Y, Lu, Gd) crystals were grown by temperature gradient technique (TGT). The Raman spectra, absorption spectra, fluorescence spectra, and fluorescence decay lifetime were measured. XRD patterns indicate that the as-synthesized samples are pure BaF2 phase. The absorption cross-section of Pr3+ ions in the BaF2 matrix can be greatly improved by co-doping R3+ ions, while improvement by Na+ and Ca2+ ions is marginal. The fluorescence characteristic of Pr3+ ions can be effectively regulated by co-doping Na+, Ca2+, R3+ (R = Y, Lu, Gd) ions of different valence states. When R3+ ions are introduced, the fluorescence spectra show the strongest orange emission and the CIE chromaticity coordinates of Pr3+ ions are also in the orange region. When single-doped Pr3+ ions and Na+ or Ca2+ ions are introduced, the fluorescence lifetime of the 3P0 level is double exponential decay, and the short lifetime is the main proportion. However, the fluorescence centers tend to homogeneous and stable by R3+ ions co-doping and the fluorescence lifetime exhibits single-exponential decay, which is fitted to 49.7 μs, 47.8 μs and 49.6 μs of (0.6%Pr3+, 10%R3+):BaF2 (R = Y, Lu, Gd), respectively. All the results show that (Pr3+, Gd3+):BaF2 and (Pr3+, Na+):BaF2 are excellent laser gain media for high-efficiency orange and red laser operation. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]

Yb,Tb:YAG crystals with various Yb3+ and Tb3+ concentration were grown by the micro-pulling-down method (μ -PD). The absorption spectra, fluorescence spectra and fluorescence decay curves of Yb,Tb:YAG crystals were measured at room temperature. Under 980 nm excitation, Yb,Tb:YAG crystals exhibited intense visible up-conversion luminescence due to the cooperative energy transfer from two Yb3+ ions to one Tb3+ ion. Under 485 nm excitation, Yb,Tb:YAG crystals yielded near-infrared down-conversion emission, ascribing to the cooperative absorption of pumping photons and cooperative energy transfer from one Tb3+ ion to two Yb3+ ions. The energy transfer processes from Yb3+ ions to Tb3+ ions were discussed, and the energy transfer efficiency was calculated. Based on studies of the obtained results, Yb3+/Tb3+ co-doped YAG crystal shows promising potential for sensing, volumetric displays, optical data storage, light emitting diodes. • Yb,Tb:YAG single crystals grown by the micro-pulling-down technique. • The cooperative energy transfer process was analyzed. • The effect of doped concentration on energy transfer efficiency was discussed. [ABSTRACT FROM AUTHOR]

Tm3+, Pr3+ co-doped Bi 4 Ge 3 O 12 (Tm,Pr:BGO) crystals with various Pr3+ doping concentration were successfully grown using the micro-pulling-down (μ-PD) method. The use of Pr3+ co-doping for deactivating the Tm3+ ions at 1.5 μm emission was investigated in the BGO single crystal for the first time. The effect of Pr3+ concentration on the spectroscopic properties of Tm,Pr:BGO crystals were demonstrated. In addition, the fluorescence lifetime of Tm3+:3F 4 level of 0.5 at.% Pr, 2 at.% Tm:BGO crystal was quenched effectively (from 5.64 ms down to 0.36 ms) and the population inversions between Tm3+:3H 4 and 3F 4 levels are enhanced to achieve a four-level laser system at 1.5 μm. • Tm,Pr:BGO crystals with different Pr3+ concentration were grown using by the micro-pulling-down method. • The effect of Pr3+ concentration on the spectroscopic properties of Tm,Pr:BGO crystals was studied. • The use of Pr3+ co-doping for deactivating the Tm3+ ions at 1.5 μm emission was investigated in BGO crystal. [ABSTRACT FROM AUTHOR]

Abstract: Spectroscopic measurements of the calcium niobate CaNb2O6 single crystal doped with samarium ions were performed. Polarized absorption and emission spectra as well as luminescence decay curves of this material were recorded as a function of temperature in the 5–300K temperature region. Analysis of low temperature spectra made it possible to determine energies of crystal field components of Sm3+ multiplets involved in the excitation and luminescence phenomena. Number of crystal field levels derived implies that Sm3+ ions in the CaNb2O6 host are accommodated in several different sites. Radiative lifetime of the 4G5/2 metastable level determined based on the Judd–Ofelt analysis of room temperature absorption spectra amounts to 777μs, a value close to that of luminescence lifetime determined from luminescence decay curve. Energy transfer between the NbO6 group and samarium ions was observed in wide temperature range. Intense luminescence related to the 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions centered at 610nm and 660nm, respectively, combined with strong absorption band near 404nm that matches perfectly the pump light provided by commercial InGaN/GaN diode lasers points at a potential of CaNb2O6:Sm3+ for the design of all-solid-state visible lasers. [Copyright &y& Elsevier]

Abstract: Spectroscopic properties of lutetium aluminum garnet Lu3Al5O12 (LuAG) single crystal doped with 1at.% of Pr3+ were investigated. The crystal was grown by the Czochralski method. Optical absorption, emission, excitation spectra and luminescence decay curves were recorded for this system in 5–500K temperature range. Excitation spectra in VUV–UV range (150–330nm) were also measured exploiting synchrotron radiation. It has been found that among bands of luminescence related to the 3PJ, 1D2 → 3HJ, 3FJ transition of Pr3+ in the visible region the 3P0 → 3H4 one, occurring ca. 488nm, is the most prominent. Luminescence lifetimes for the 3P0,1 and 1D2 levels were estimated to be 13 and 200μs respectively (at room temperature). VUV-excited emission spectrum stretches over the whole visible region. It has been concluded that the material under study is a promising phosphor that can be efficiently pumped by broad absorption bands centered at 240 and 280nm. [Copyright &y& Elsevier]

A Nd:BGSO crystal with the dimensions of Φ2 × 131 mm3 has been grown successfully by the micro-pulling-down method. The peak absorption cross-section at 808 nm was calculated to 0.98 × 10−20 cm2 with full-width at half-maximum of 17.4 nm. The stimulated emission cross-section was obtained to be 3.15 × 10−20 cm2 at 1063 nm. The fluorescence and radiative lifetimes of 4F 3/2 level were 248 μs and 300 μs respectively. All results indicate that the Nd: BGSO single crystal would be a promising near-IR solid-state laser material. [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]

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]

Photograph of Yb,Ho:YAG crystals grown by the μ-PD method. (a) Yb = 0.05, (b) 0.1, (c) 0.15. • Y 3 Al 5 O 12 (YAG) single crystals doped with a fixed Ho3+ content of 0.5 at.% and various Yb3+ contents (Yb = 5, 10 and 15 at.%) have been successfully grown by the micro-pulling-down (μ-PD) method. Y 3 Al 5 O 12 (YAG) single crystals doped with a fixed Ho3+ content of 0.5 at.% and various Yb3+ contents (Yb = 5, 10 and 15 at.%) have been successfully grown by the micro-pulling-down (μ-PD) method. The absorption spectra, fluorescence spectra and fluorescence decay curves were recorded at room temperature. The intense emission of Yb,Ho:YAG crystal centered at 2 μm corresponds to the 5I 7 → 5I 8 transition. Three intense emissions centered at 524–569 nm, 623–691 nm and 744–746 nm, correspond to the 5F 4 + 5S 2 → 5I 8 , 5F 5 → 5I 8 and 5F 4 + 5S 2 → 5I 7 transitions, respectively. The possible energy transfer mechanisms were discussed intensively. [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]

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]