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Ho‐doped sesquioxide is one of the most important laser gain media for 2 micron wavelength band laser applications. It is hard to be transparent by sintering because of its high melting point. Herein, the structural and spectral properties of 0.5 at% Ho:(Y1−xScx)2O3 (x = 0, 0.3, 0.5, 0.7, 1.0) ceramics fabricated by vacuum pressureless sintering are studied. Then, 0.5 at% Ho:(Y0.7Sc0.3)2O3 transparent ceramics with 1.0 at% ZrO2 as a sintering aid are prepared by vacuum pressureless presintering (1680 °C for 4 h) combined with hot isostatic pressing sintering treatment (1600 °C/190 MPa for 3 h). The transmittance of Ho:(Y0.7Sc0.3)2O3 ceramic reaches 80.8% at 1100 nm (6 mm in thickness), which is close to its theoretic value. The addition of ZrO2 has no significant influence on spectroscopic properties of 0.5 at% Ho:(Y0.7Sc0.3)2O3 ceramics. [ABSTRACT FROM AUTHOR]

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]

The combination of its high electron mobility, broadband absorption and ultrafast luminescence make graphene attractive for optoelectronic and photonic applications, including transparent electrodes, mode-locked lasers and high-speed optical modulators. Photo-excited carriers that have not cooled to the temperature of the graphene lattice are known as hot carriers, and may limit device speed and energy efficiency. However, their roles in charge and energy transport are not fully understood. Here, we use time-resolved scanning photocurrent microscopy to demonstrate that hot carriers, rather than phonons, dominate energy transport across a tunable graphene p-n junction excited by ultrafast laser pulses. The photocurrent response time varies from 1.5 ps at room temperature to 4 ps at 20 K, implying a fundamental bandwidth of ?500 GHz (refs 12, 13, 21). Gate-dependent pump-probe measurements demonstrate that both thermoelectric and built-in electric field effects contribute to the photocurrent, with the contribution from each depending on the junction configuration. The photocurrent produced by a single pulsed laser also displays multiple polarity reversals as a function of carrier density, which is a possible signature of impact ionization. [ABSTRACT FROM AUTHOR]

Bioluminescence resonance energy transfer (BRET) is a natural biophysical phenomenon that underlies an emerging technique to monitor protein–protein interactions in living cells in real time. Here, we present a series of technical advances to enhance the utility of the BRET assay in plants. A series of recombination cloning vectors was generated to accelerate the expression of proteins tagged with Renilla luciferase or yellow fluorescent protein under transient assay conditions and in stable transgenic plants. Working in stably transformed Arabidopsis or tobacco, we then detected BRET between three pairs of candidate interaction partners: dimerization of the E3 ubiquitin ligase COP1, interaction between COP1 and the B-box protein STH, and interaction between the light regulatory bZip transcription factors HY5 and HYH. A codon-optimized version of the Renilla luciferase gene resulted in improved expression in Arabidopsis. Renilla luciferase was active in a variety of subcellular organelles, including plastids, mitochondria, peroxisomes and Golgi stacks. In a survey of the Arabidopsis light signaling machinery as a model system, we estimated the likelihood that a known protein–protein interaction can be documented using BRET. Finally, we show that Renilla luciferase may serve as a reporter of protein stability in a cycloheximide chase assay. [ABSTRACT FROM AUTHOR]

Abstract: Infrared (1.2–1.6μm) luminescence in a ytterbium aluminium garnet (YbAG) crystal, doped with Cr (0.05at.%) ions, was investigated under CW laser diode pumping (λ =940nm). The Cr4+ emission band was observed with its peak at 1.34μm and measured to be about 1.3 times with respect to Yb3+ IR luminescence (λ =1.03μm). We demonstrate that for the excitation wavelength of 940nm Yb3+ ions act as sensitizers of the 3B2(3T2)–3B1(3A2) emission of Cr4+ ions. This crystal is promising as a high-efficient system for tunable laser (1.2–1.6μm) output. [Copyright &y& Elsevier]

Abstract: In this paper, we present results on upconversion luminescence performed on Yb3+-doped yttrium aluminum garnets under 940nm excitation. The upconversion luminescence was ascribed to Yb3+ cooperative luminescence and the presence of rare earth impurity ions. The cooperative luminescence spectra as a function of Yb concentration were measured and the emission intensity variation with Yb concentration was discussed. Yb3+ energy migration quenched the cooperative luminescence of Yb:YAG crystals with doping level over 15at%. [Copyright &y& Elsevier]

Abstract: Infrared (1.2–1.6μm) luminescence in a yttrium aluminium garnet (YAG) crystal, co-doped with Yb (10 at.%) and Cr (0.05 at.%) ions, was investigated under CW laser diode pumping (λ =940nm). The Cr4+ emission band was observed with its peak at 1.35μm and measured to be about 6% with respect to Yb3+ IR luminescence (λ =1.03μm). Analysis of the crystal absorption and luminescence spectra allows one to conclude that Yb3+–Cr4+ energy transfer is a mechanism responsible for the 3B2(3T2)–3B1(3A2) emission of Cr4+ ions. This crystal is promising as an efficient source of the near infrared emission. [Copyright &y& Elsevier]

Al 2 O 3 –Y 3 Al 5 O 12 :Ce (Al 2 O 3 -YAG:Ce) eutectic with weak attenuation at high temperature has a wide range of applications in high-power white light solid-state lighting. However, the general color rendering index (general CRI, R a , the average value of R 1 -R 8) of phosphor-converted white light-emitting diode (Pc-WLED) based on this material is usually no higher than 70 (CCT < 6500 K). We grew Al 2 O 3 -YAG eutectics doped with three ions of Ce3+, Pr3+, and Cr3+ by the micro pulling-down (μ-PD) method to improve the R a through the co-luminescence and energy-transfer. The co-luminescence and energy-transfer were analyzed by the excitation-emission spectrum and the spectral power distribution. Results show that the energy-transfer between Ce3+ and Pr3+ ions in Al 2 O 3 -YAG:Ce, Pr occurs with each other, visibly enhancing the emission at around 610 nm and 694 nm, increases the R a by 8.4 compared to Al 2 O 3 -YAG:Ce. Moreover, the R a of the Al 2 O 3 -YAG:Ce and Al 2 O 3 -YAG:Cr stacked Pc-WLED increases by 20.4 compared to Al 2 O 3 -YAG:Ce, reaching 78.7. In addition, (R 9 , the special CRI for strong red, is 59.). In addition, the annealed (H 2) single-doped eutectics have little change compared to unannealed ones in luminescence, but the co-doped ones with multiple ions have a significant change. Significantly, the luminous efficiency of Al 2 O 3 -YAG:Ce after annealing is only increased by 4%, while that of Al 2 O 3 -YAG:Ce, Pr is increased by 13%. These studies show that the CRI of Pc-WLED base on Al 2 O 3 -YAG:Ce eutectic can be improved by ion co-doping in eutectic or superposition of Al 2 O 3 -YAG eutectic doped with other ions. • The co-luminescence of Ce3+ and Pr3+ in Al 2 O 3 –YAG enhancing the emission of 610 nm and 694 nm, increases the R a by 8.4. • The Cr3+ in Al 2 O 3 –YAG:Ce absorbs the emission spectra of the Ce3+ but quenches the fluorescence produced by Ce3+, which seriously hinders the luminescence of Ce3+. • The R a of the Al 2 O 3 –YAG:Ce and Al 2 O 3 –YAG:Cr stacked phosphor-converted LED increases by 20.4, reaching 78.7 (R 9 = 59). • The luminous efficiency of Al 2 O 3 –YAG:Ce after annealing is only increased by 4%, while that of Al 2 O 3 -YAG:Ce, Pr is increased by 13%. • It is found that the co-doping of Pr3+ ions will increase the probability of Ce4+ in Al 2 O 3 -YAG:Ce. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, some results on visible luminescence performed on Yb3+-doped gadolinium gallium garnets under 165 and 940nm excitation were presented. The upconversion luminescence was ascribed to Yb3+ cooperative luminescence and the presence of rare earth impurity ions. The gain cross-sections of Yb:GGG crystal as a function of excited-state population fraction β were studied. Emission spectra under 165nm at 20K showed there was no charge transfer luminescence in Yb:GGG. [Copyright &y& Elsevier]

Abstract: In this paper, single crystal of ytterbium (Yb) doped Ca5(PO4)3F (FAP) has been grown along the c-axis by using the Czochralski method. The segregation coefficients of Yb3+ in the Yb:FAP crystal has been determined by ICP-AES method. The absorption spectrum, fluorescence spectrum and fluorescence lifetime of the Yb:FAP crystal has been also measured at room temperature. In the absorption spectra, there are two absorption bands at 904 and 982nm, respectively, which are suitable for InGaAs diode laser pumping. The absorption cross-section (σ abs) is 5.117×10−20 cm2 with an FWHM of 4nm at 982nm. The emission cross-section (σ em) is 3.678×10−20 cm2 at 1042nm. Favorable values of the absorption cross-section at about 982nm are promising candidates for laser diode (LD) pumping. [Copyright &y& Elsevier]

BGO single crystals doped with Er3+, Tm3+ and Ho3+ rare-earth ions were prepared in the form of rod-type crystal fibers via the micro-pulling down technique to perform an extensive investigation of their visible, near- and mid-infrared luminescence properties and to really decide on their interest as solid-state laser media in the various spectral domains. Revisiting and completing the absorption spectra already available in the literature led to the derivation of more reliable "effective" radiative lifetimes and branching ratios. Registration of the fluorescence decays of the most important emitting levels versus dopant concentrations led for the first time to an unambiguous determination of "intrinsic" emission lifetimes – corresponding to negligible contributions from inter-ionic energy-transfers - and non-radiative multiphonon relaxation rates. Such data also allowed for the determination of the dominant phonon energy which comes into play in the electron-phonon coupling responsible for these multiphonon relaxation processes and for its lattice vibration origin, i.e. a high phonon energy of the order of 820 cm−1 corresponding to the coupling between bending vibrations of (GeO 4)4- tetrahedra and vibrations corresponding to motions of these (GeO 4)4- tetrahedra against the Bi3+ ions for which the rare-earth dopant ions substitute. Using the above data and different methods for the calibration of the registered emission spectra in cross section unit and for the derivation of gain cross section curves finally show that mid-infrared emissions of Er:BGO, Tm:BGO and Ho:BGO around 1.55 μm, 1.9 μm and 2 μm, respectively, occur with comparable gain cross sections as in the most important reference mid-infrared laser materials, although over slightly shifted thus complementary spectral domains. It is shown that potentialities also exist with Tm:BGO in the blue, deep-red and near-infrared spectral domains around 470 nm, 800 nm and 1.45 μm, by pumping the crystals with conventional pump sources and using some suitable co-dopants to avoid detrimental self-terminating processes. • Bi 4 Ge 3 O 12 rod-type crystal fibers doped with Er3+, Tm3+ and Ho3+ ions are successfully grown by using the micro-pulling down technique. • An extensive spectroscopic investigation is performed from the near-UV to the mid-infrared. • Effective radiative and intrinsic emission lifetimes are unambiguously determined for all the important emitting levels. • The origin and the energy of the phonons responsible for the non-radiative multiphonon relaxation of the emitting levels are clearly identified. • Emission and gain cross section spectra show the interest of Er3+, Tm3+ and Ho3+ doped BGO crystals for the high power mid-infrared laser application. [ABSTRACT FROM AUTHOR]

Sm3+ doped yttria transparent ceramics (Sm x Y 1-x) 2 O 3 (x = 0.01, 0.015, 0.03) were fabricated by Spark Plasma Sintering method. Absorption spectra, as well as emission spectra and luminescence lifetime were carried out at room temperature. Judd-Ofelt (J-O) theory was used to calculate the Ω t (t = 2, 4, 6) intensity parameters. The spontaneous transition probabilities, radiative lifetime, branching ratio, and stimulated emission cross-sections have been calculated for 4G 5/2 excited level. The emission cross section for the 4G 5/2 → 6H 7/2 transition at about 607 nm was calculated to be 6.73 × 10−22 cm2. The results indicate that Sm:Y 2 O 3 ceramic may be a potential reddish orange-light laser material around 607 nm. [ABSTRACT FROM AUTHOR]

The luminescence properties of 0.5%Pr-doped BGO crystals grown by using the micro-pulling down technique were carefully investigated. Room temperature absorption spectra were registered and analyzed within the framework of the Judd-Ofelt formalism and the best fit to the data is obtained by using a modified treatment allowing for the admixture of intensity enabling wave-functions. The results indicate 3P 0 and 1D 2 radiative lifetimes of about 5.7 μs and 79 μs, in perfect agreement with the time-constants derived from the measured fluorescence decays at room and liquid-nitrogen temperatures. Registration of time-resolved emission and excitation spectra and calibration of the 3P 0 emission spectrum in cross section unit clearly indicate that Pr-doped BGO could be the first isotropic crystalline material leading to efficient diode-pumped laser operation at room temperature with laser performances, at least in the deep-red spectral region, comparable to that found with the most important anisotropic Pr-doped fluoride and oxide crystals. • Pr:Bi 4 Ge 3 O 12 crystal fibers are successfully grown by micro-pulling down. • Absorption spectra are analyzed by using the Judd-Ofelt formalism. • Emission, excitation spectra are registered from the near-UV to the deep-Red. • It is found a 3P0 emission lifetime of 5.7 μs for a quantum yield close to 1. • Record emission cross-sections are obtained in the red and deep-red. [ABSTRACT FROM AUTHOR]

Ce,Tb,Gd:YAG-Al 2 O 3 eutectic crystal phosphor plates (ECPPs) were grown by the micro-pulling-down (μ-PD) method to adjust correlated color temperature (CCT) and color rendering index (Ra) for high-power warm white LED applications. Tb3+ and Gd3+ ions in Ce:YAG-Al 2 O 3 play a positive role in spectra adjustment based on the structural and luminescent properties investigations. Tb3+ ions enhance the fluorescence lifetime of Ce3+ ions from 61.1 to 63.8 ns and improve the luminescence efficiency, and the highest optical-optical conversion efficiency (OCE) is 270.56 lm/W. Corresponding luminescence shift from cold white to greenish yellow. Gd3+ ions increase the peak wavelength from 554 to 564 nm and improve the Ra value, and the maximum Ra is 75.5. Corresponding luminescence is shifted from cold white to reddish violet. In addition, the luminescence of Ce,Tb,Gd:YAG-Al 2 O 3 ECPPs is adjusted to warm white with CIE coordinate (0.374, 0.364) and CCT of 4102 K, and Ra of 73.0, which is of great significance for realizing the high-power warm white LED lighting. • Tb3+ ions increased the fluorescence lifetime of Ce3+ ions by ∼17%， and improved the luminescence efficiency with the highest OCE of 270.56 lm/W. And Gd3+ ions increased the peak wavelength of emission from 554 nm to 564 nm and improved the Ra from 65.5 to 75.5. • The Ce,Tb,Gd:YAG-Al 2 O 3 ECPP has excellent performance with a low CCT of ∼4100 K and a CIE coordinate of (0.374, 0.364). • The CRI of Ce,Tb,Gd:YAG-Al 2 O 3 ECPP reached 73.0. [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]

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]

• A series of 0.6 at% Pr:CaF 2 -RF 3 (R= Y3+, Gd3+, Lu3+) crystals were successfully grown by the temperature gradient technique(TGT) method. • By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. • The spectral performance and spectral quality factor of the crystals were systematically described and compared for the first time. • The spectral modulation effect caused by Y3+, Gd3+ and Lu3+ co-doping ion was discussed. A series of 0.6 at% Pr:CaF 2 -RF 3 (R = Y3+, Gd3+, Lu3+) crystals have been successfully grown by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, and fluorescence decay curves were measured and analyzed at room temperature. When the R3+ concentration is higher than a certain value, the diffraction peaks of Pr:CaF 2 -RF 3 crystals were well indexed to the (Ca,Y)F 2 phase. By co-doping R3+ ion (R=Y3+, Gd3+, Lu3+), the spectral performance of the crystals could be significantly improved and the function effect is also different. For 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal, the fluorescence lifetime of 3P 0 energy level was fitted to be 45.46 µs, and the emission cross sections of 3P 0 →3H 6 (605 nm), and 3P 0 →3F 2 (641 nm) were calculated to be 1.78 × 10−20 cm2, and 4.61 × 10−20 cm2 with the full width at half (FWHM) of 20.1 nm and 6.8 nm, respectively. The 0.6 at% Pr, 28.5 at% Y:CaF 2 crystal could be favorble laser medium for ultra-fast laser opreration at 605 nm and 641 nm. For 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals, the spectral quality factors σ em• τ f of 3P 0 →3F 2 transition (642 nm) were calculated to be 614.18 × 10−20 cm2•µs and 506.36 × 10−20 cm2•µs with the FWHM of 3.7 nm and 5.3 nm. All the results show that 0.6 at% Pr, 18 at% Gd:CaF 2 and 0.6 at% Pr, 10 at% Lu:CaF 2 crystals are promising gain media for high-efficiency visible laser output at 642 nm, which would compete with commercial Pr: YLF crystal in the future. [ABSTRACT FROM AUTHOR]

Abstract: Yb-doped PbClF crystals were obtained by a modified Bridgman method. Broadband emission (FWHM=58nm) with long lifetime (5.33ms) was observed in 2.0% Yb3+-doped PbClF crystals. The Stark splitting of Yb3+ 2F7/2 level was calculated to be 801cm−1 in 0.5% Yb3+-doped PbClF crystals, and the corresponding population of lower laser level is about 2.13%. All the results indicated that Yb-doped PbClF crystals should be a promising material to ultrashort pulses output at 1.0μm. [Copyright &y& Elsevier]

Abstract: Ytterbium-doped calcium pyroniobate single crystal has been grown for the first time. Spectral properties of Yb: Ca2Nb2O7 were investigated by emission and absorption spectra. Its cooperative luminescence and fluorescence lifetime were also studied. Yb ions in Ca2Nb2O7 showed very broad absorption and emission bandwidth and relatively large absorption and emission cross-sections. Along with other optical properties, this Yb-doped crystal would be a potential self-frequency doubling femtosecond laser gain material. [Copyright &y& Elsevier]

Abstract: For the first time, a quaternary doping system of Er3+, Yb3+, Ce3+, Na+: CaF2 single crystal was demonstrated to have high fluorescence yield in the 1.5μm region. Through a simplified model, the branching ratio of the Er3+ 4I11/2→4I13/2 transition was estimated to be improved more than 40 times by the deactivating effect of Ce3+ in the quaternary-doped CaF2 crystal with dopants of 0.2-at% Er3+ and 2.0-at% Ce3+. Owing to the broad emission bandwidth and large emission cross-section, the quaternary-doped CaF2 system shows the great potential to achieve the high laser performance in the 1.5μm region. [Copyright &y& Elsevier]

Abstract: Gd2SiO5 (GSO) single crystal codoped with Yb3+ and Er3+ (Abbr. as Er:Yb:GSO) was successfully grown by the Czochralski (CZ) method for the first time and the spectral characteristics were investigated. The absorption and fluorescence spectra were measured. The emission lifetime of the 4I13/2–Er-level was measured to be 5.84ms and the emission cross-section at 1529nm was calculated to be 1.03×10−20 cm2. The results indicate that Er:Yb:GSO is a potential laser material at ∼1.55μm wavelength region. [Copyright &y& Elsevier]

Yb,Pr:CaF 2 crystals have been grown successfully by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, fluorescence decay lifetime of Pr3+ ions in CaF 2 crystal sensitized by different Yb3+ ions concentration have been measured. The effective J-O intensity parameters were fitted to be Ω 2 =0.36 × 10−20cm2, Ω 4 =2.89 × 10−20cm2, Ω 6 =6.69 × 10−20cm2 for 0.3 at.%Pr,1.5 at.%Yb:CaF 2. And the emission cross sections of 3P 1 →3H 5 (535 nm), and 3P 0 →3F 4 (750 nm) are calculated to be 2.02 × 10−20cm2, and 2.50 × 10−20cm2 with the FWHM of 17.2 nm, and 10.5 nm, respectively. The fluorescence lifetime of 3P 0 has achieved great increasing by sensitizing of Yb3+ ion. Not only the up-conversion luminescence can be achieved, but also the broad band emission from 1D 2 energy level can be observed. The results show that Yb,Pr:CaF 2 could be a potential laser gain medium for visible and near-IR laser operation. • Not only the up-conversion luminescence can be achieved, but also the broad band emission from 1D 2 energy level can be observed by Yb3+ ion sensitizing. • Spectral properties and Judd-Ofelt parameters of Yb,Pr:CaF 2 crystal were investigated and analysed. [ABSTRACT FROM AUTHOR]

We report on the comparative growth and spectroscopy of Eu3+-doped Y 3 Al 5 O 12 (YAG) and Y 3 ScAl 4 O 12 crystals grown by the micro-pulling-down (μ-PD) method. The structure of the as-grown crystals was determined by X-ray diffraction (XRD) and Raman spectroscopy. The absorption spectra of the crystals are dominated by a strong line centered at 395 nm, matching well with the emission of commercial ultraviolet laser diodes. The Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals exhibit strongest red emission centered at 710 nm and the full width at half maximum (FWHM) was calculated to be 2.03 and 3.19 nm, respectively. The fluorescence decay curves of 5D 0 levels were measured and discussed. All the results indicate that the Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals are promising candidates for red luminescent/laser materials. • Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were successfully grown by the micro-pulling-down technique for the first time. • The structure parameters of Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were investigated by XRD. • Spectral parameters of Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were obtained and compared. [ABSTRACT FROM AUTHOR]