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V Gorbenko - One of the best experts on this subject based on the ideXlab platform.

  • luminescence and Energy Transfer Processes in ce 3 activated gd tb 3 al 5 o 12 single crystalline films
    Journal of Luminescence, 2017
    Co-Authors: K Bartosiewicz, V Babin, J Mares, Yuriy Zorenko, V Gorbenko, A Beitlerova, A Iskaliyeva, Z Bryknar
    Abstract:

    Abstract The luminescence and scintillation properties of gadolinium terbium aluminium garnet single crystalline films, Gd3−xTbxAl5O12, doped with Ce3+ are investigated as a function of the Gd/Tb ratio with the aim of an improved understanding of the Energy Transfer Processes between Ce3+ and Tb3+ ions in the aluminium garnet hosts. Upon replacing the Gd3+ by Tb3+, the crystal field splitting for the 5d Energy level of Ce3+ does not change significantly, due to comparable sizes of the Gd3+ and Tb3+ cations. Temperature dependence of the decay time of Tb3+ and Ce3+ luminescence confirms an efficient Energy Transfer from the Tb3+ to Ce3+ and provides a qualitative understanding of this process. Furthermore, bidirectional Energy Transfer Processes between the Ce3+ and Tb3+ are revealed. Scintillation decays under α-particles excitation show the presence of the fast and slow sub-microsecond components.

  • luminescence and Energy Transfer Processes in lu tb 3al5o12 single crystalline films doped with ce3
    Journal of Luminescence, 2016
    Co-Authors: K Bartosiewicz, V Babin, M Nikl, J Mares, Yuriy Zorenko, V Gorbenko
    Abstract:

    Abstract The luminescence properties of terbium lutetium aluminium garnet single crystalline films, Lu 3− x Tb x Al 5 O 12 , doped with Ce 3+ are investigated as a function of the Tb/Lu ratio with aim of an improved understanding of the Energy Transfer Processes between Ce 3+ and Tb 3+ ions in the aluminium garnet hosts. Due to replacing the smaller Lu 3+ ion with the larger Tb 3+ ion, the crystal field splitting for the 5d Energy levels of Ce 3+ ions increases, causing the shift of the lowest 5d state of Ce 3+ below the 5 D 4 Energy level of Tb 3+ . This allows for the efficient Energy Transfer from Tb 3+ to Ce 3+ even at the low temperatures. The measurements of temperature dependence of the decay time of Tb 3+ and Ce 3+ luminescence confirm an efficient Energy Transfer from Tb 3+ to Ce 3+ and provide a qualitative understanding of this process. Furthermore, bi-directional Energy Transfer Processes between Ce 3+ and Tb 3+ are revealed. Scintillation decays under α-particles excitation show presence of the fast and slow sub-microsecond components.

  • bi3 pr3 Energy Transfer Processes and luminescent properties of luag bi pr and yag bi pr single crystalline films
    Journal of Luminescence, 2013
    Co-Authors: M Nikl, J Mares, Yuriy Zorenko, V Gorbenko, A Beitlerova, V Savchyn, T Zorenko, Vitezslav Jary
    Abstract:

    Abstract Absorption, cathodoluminescence, excitation spectra of photoluminescence (PL) and PL decay kinetics were studied at 300 K for the double doped with Bi 3+ –Pr 3+ and separately doped with Bi 3+ and Pr 3+ Lu 3 Al 5 O 12 (LuAG) and Y 3 Al 5 O 12 (YAG) single crystalline film (SCF) phosphors grown by the liquid phase epitaxy method. The emission bands in the UV range arising from the intrinsic radiative transitions of Bi 3+ based centers, and emission bands in the visible range, related to the luminescence of excitons localized around Bi 3+ based centers, were identified both in Bi–Pr and Bi-doped LuAG and YAG SCFs. The Energy Transfer Processes from the host lattice simultaneously to Bi 3+ and Pr 3+ ions and from Bi 3+ to Pr 3+ ions were investigated. Competition between Pr 3+ and Bi 3+ ions in the Energy Transfer Processes from the LuAG and YAG hosts was evidenced. The strong decrease of the intensity of Pr 3+ luminescence both in LuAG:Pr and YAG:Pr SCFs phosphors, grown from Bi 2 O 3 flux, is observed due to the quenching influence of Bi 3+ flux related impurity. Due to overlap of the UV emission band of Bi 3+ centers with the f–d absorption bands of Pr 3+ ions in the UV range and the luminescence of excitons localized around Bi ions with the f–f absorption bands of Pr 3+ ions in the visible range, an effective Energy Transfer from Bi 3+ ions to Pr 3+ ions takes place in LuAG:Bi,Pr and YAG:Bi,Pr SCFs, resulting in the appearance of slower component in the decay kinetics of the Pr 3+ d–f luminescence.

Yuriy Zorenko - One of the best experts on this subject based on the ideXlab platform.

  • luminescence and Energy Transfer Processes in ce 3 activated gd tb 3 al 5 o 12 single crystalline films
    Journal of Luminescence, 2017
    Co-Authors: K Bartosiewicz, V Babin, J Mares, Yuriy Zorenko, V Gorbenko, A Beitlerova, A Iskaliyeva, Z Bryknar
    Abstract:

    Abstract The luminescence and scintillation properties of gadolinium terbium aluminium garnet single crystalline films, Gd3−xTbxAl5O12, doped with Ce3+ are investigated as a function of the Gd/Tb ratio with the aim of an improved understanding of the Energy Transfer Processes between Ce3+ and Tb3+ ions in the aluminium garnet hosts. Upon replacing the Gd3+ by Tb3+, the crystal field splitting for the 5d Energy level of Ce3+ does not change significantly, due to comparable sizes of the Gd3+ and Tb3+ cations. Temperature dependence of the decay time of Tb3+ and Ce3+ luminescence confirms an efficient Energy Transfer from the Tb3+ to Ce3+ and provides a qualitative understanding of this process. Furthermore, bidirectional Energy Transfer Processes between the Ce3+ and Tb3+ are revealed. Scintillation decays under α-particles excitation show the presence of the fast and slow sub-microsecond components.

  • luminescence and Energy Transfer Processes in lu tb 3al5o12 single crystalline films doped with ce3
    Journal of Luminescence, 2016
    Co-Authors: K Bartosiewicz, V Babin, M Nikl, J Mares, Yuriy Zorenko, V Gorbenko
    Abstract:

    Abstract The luminescence properties of terbium lutetium aluminium garnet single crystalline films, Lu 3− x Tb x Al 5 O 12 , doped with Ce 3+ are investigated as a function of the Tb/Lu ratio with aim of an improved understanding of the Energy Transfer Processes between Ce 3+ and Tb 3+ ions in the aluminium garnet hosts. Due to replacing the smaller Lu 3+ ion with the larger Tb 3+ ion, the crystal field splitting for the 5d Energy levels of Ce 3+ ions increases, causing the shift of the lowest 5d state of Ce 3+ below the 5 D 4 Energy level of Tb 3+ . This allows for the efficient Energy Transfer from Tb 3+ to Ce 3+ even at the low temperatures. The measurements of temperature dependence of the decay time of Tb 3+ and Ce 3+ luminescence confirm an efficient Energy Transfer from Tb 3+ to Ce 3+ and provide a qualitative understanding of this process. Furthermore, bi-directional Energy Transfer Processes between Ce 3+ and Tb 3+ are revealed. Scintillation decays under α-particles excitation show presence of the fast and slow sub-microsecond components.

  • bi3 pr3 Energy Transfer Processes and luminescent properties of luag bi pr and yag bi pr single crystalline films
    Journal of Luminescence, 2013
    Co-Authors: M Nikl, J Mares, Yuriy Zorenko, V Gorbenko, A Beitlerova, V Savchyn, T Zorenko, Vitezslav Jary
    Abstract:

    Abstract Absorption, cathodoluminescence, excitation spectra of photoluminescence (PL) and PL decay kinetics were studied at 300 K for the double doped with Bi 3+ –Pr 3+ and separately doped with Bi 3+ and Pr 3+ Lu 3 Al 5 O 12 (LuAG) and Y 3 Al 5 O 12 (YAG) single crystalline film (SCF) phosphors grown by the liquid phase epitaxy method. The emission bands in the UV range arising from the intrinsic radiative transitions of Bi 3+ based centers, and emission bands in the visible range, related to the luminescence of excitons localized around Bi 3+ based centers, were identified both in Bi–Pr and Bi-doped LuAG and YAG SCFs. The Energy Transfer Processes from the host lattice simultaneously to Bi 3+ and Pr 3+ ions and from Bi 3+ to Pr 3+ ions were investigated. Competition between Pr 3+ and Bi 3+ ions in the Energy Transfer Processes from the LuAG and YAG hosts was evidenced. The strong decrease of the intensity of Pr 3+ luminescence both in LuAG:Pr and YAG:Pr SCFs phosphors, grown from Bi 2 O 3 flux, is observed due to the quenching influence of Bi 3+ flux related impurity. Due to overlap of the UV emission band of Bi 3+ centers with the f–d absorption bands of Pr 3+ ions in the UV range and the luminescence of excitons localized around Bi ions with the f–f absorption bands of Pr 3+ ions in the visible range, an effective Energy Transfer from Bi 3+ ions to Pr 3+ ions takes place in LuAG:Bi,Pr and YAG:Bi,Pr SCFs, resulting in the appearance of slower component in the decay kinetics of the Pr 3+ d–f luminescence.

O L Malta - One of the best experts on this subject based on the ideXlab platform.

  • analysis of Energy Transfer Processes in yb3 tb3 co doped low silica calcium aluminosilicate glasses
    Journal of Applied Physics, 2011
    Co-Authors: I A A Terra, L J Borrerogonzalez, L A O Nunes, Marcos Paulo Belancon, J H Rohling, M L Baesso, O L Malta
    Abstract:

    Energy Transfer Processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses were analyzed. Luminescence and time-resolved measurements were used to study upconversion Processes, such as Yb-Tb cooperative sensitization, Yb-Yb cooperative luminescence, and Yb-Tb cross relaxation. The quantum cross relaxation efficiency was evaluated as a function on the Yb3+ concentration, and the maximum estimated value was approximately 51%. In addition, the intensity of the upconversion luminescence from the Tb3+:5D4 level decreased by two orders of magnitude comparing the value at room temperature with that at 123 K. As a consequence, Yb-Yb cooperative luminescence around 500 nm became comparable with the intensity of upconversion from the Tb3+:5D4 level. Furthermore, a dependence of the upconversion kinetics luminescence on temperature was observed. The upconversion rise time was constant and equal to 65 μs for temperatures between 296 to 473 K and decreased from 65 to 19 μs, without variation in the de...

  • analysis of Energy Transfer Processes in yb3 tb3 co doped low silica calcium aluminosilicate glasses
    Journal of Applied Physics, 2011
    Co-Authors: I A A Terra, L J Borrerogonzalez, Marcos Paulo Belancon, J H Rohling, M L Baesso, Luiz Antonio De Oliveira Nunes, O L Malta
    Abstract:

    Energy Transfer Processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses were analyzed. Luminescence and time-resolved measurements were used to study upconversion Processes, such as Yb-Tb cooperative sensitization, Yb-Yb cooperative luminescence, and Yb-Tb cross relaxation. The quantum cross relaxation efficiency was evaluated as a function on the Yb3+ concentration, and the maximum estimated value was approximately 51%. In addition, the intensity of the upconversion luminescence from the Tb3+:5D4 level decreased by two orders of magnitude comparing the value at room temperature with that at 123 K. As a consequence, Yb-Yb cooperative luminescence around 500 nm became comparable with the intensity of upconversion from the Tb3+:5D4 level. Furthermore, a dependence of the upconversion kinetics luminescence on temperature was observed. The upconversion rise time was constant and equal to 65 μs for temperatures between 296 to 473 K and decreased from 65 to 19 μs, without variation in the decay part, when the temperature was lowered from 296 to 123 K. These results were explained by a phonon-assisted cooperative sensitization process for the population of the Tb3+:5D4 level.

Markus Pollnau - One of the best experts on this subject based on the ideXlab platform.

  • Stochastic model of Energy Transfer Processes among rare earth ions
    Fiber Lasers and Glass Photonics: Materials through Applications, 2018
    Co-Authors: P. Loiko, Markus Pollnau
    Abstract:

    Energy-Transfer Processes strongly affect the performance of lanthanide-doped photonic devices. In this work, we introduce a simple stochastic model of Energy-Transfer Processes and successfully apply it to the example of crossrelaxation (CR) and Energy-Transfer upconversion (ETU) in amorphous Al 2 O 3 :Tm 3+ waveguides on silicon intended for lasers operating at ~2 μm. The stochastic model is based on the rate-equation formalism and considers two spectroscopically distinct ion classes, namely single ions and ions with neighbours (pairs and clusters), with the corresponding ion fractions being dependent on the doping concentration. We prove that a more accurate description of the luminescence properties of amorphous Al 2 O 3 :Tm 3+ is obtained when accounting for the presence of these distinct ion classes. Based on the developed model, we derive microscopic CR and ETU parameters of CCR = 5.83×10 -38 cm 6 s -1 , C ETU1 = 0.93×10 -40 cm 6 s -1 , and C ETU2 = 7.81×10 -40 cm 6 s -1 , and determine the laser quantum efficiency η q of excitation of Tm 3+ ions in the upper laser level. For the maximum Tm 3+ concentration of 5.0×10 20 cm -3 studied experimentally in this investigation, η q reaches 1.73. Furthermore, the transition cross-sections at the pump and laser wavelengths are determined. For the 3 H 6 → 3 F 4 transition, the maximum stimulated-emission cross-section is σ e = 0.47 × 10 -20 cm 2 at 1808 nm.

  • Energy-Transfer Processes Among Non-Homogeneously Distributed Rare-Earth Ions and Impact on Amplification and Lasing
    2018 20th International Conference on Transparent Optical Networks (ICTON), 2018
    Co-Authors: Irene Carrasco, P. Loiko, L. Agazzi, Markus Pollnau
    Abstract:

    Energy-Transfer Processes such as Energy-Transfer upconversion are often detrimental to the performance of rare-earth-doped amplifiers and lasers on the typical luminescence transitions in the near-infrared spectral region between 1-2 μm. In order to quantify the influence of these interionic Processes on amplification and lasing, not only luminescence decay curves have to be measured, but also the population dynamics of the electronic level scheme need to be modeled. The usually encountered non-homogeneous ion distributions complicate the situation. Here we present a stochastic model of Energy-Transfer Processes that takes a statistical ion distribution into account. The influence of Energy-Transfer upconversion and cross-relaxation on amplification and lasing on the 1.06 μm transition in Nd3+, the 1.53 μm transition in Er3+, or the 1.84 μm transition in Tm3+ under these conditions is investigated.

  • Stochastic Model of Energy-Transfer Processes Among Rare-Earth Ions. Example of Al2O3:Tm3+
    The Journal of Physical Chemistry C, 2016
    Co-Authors: P. Loiko, Markus Pollnau
    Abstract:

    Energy-Transfer Processes strongly affect the performance of lanthanide-doped photonic devices. In this work, we introduce a simple stochastic model of Energy-Transfer Processes and successfully apply it to the example of cross-relaxation (CR) and Energy-Transfer upconversion (ETU) in amorphous Al2O3:Tm3+ waveguides on silicon intended for lasers operating at ∼2 μm. The stochastic model is based on the rate-equation formalism and considers two spectroscopically distinct ion classes, namely single ions and ions with neighbors (pairs and clusters), with the corresponding ion fractions being dependent on the doping concentration. We prove that a more accurate description of the luminescence properties of amorphous Al2O3:Tm3+ is obtained when accounting for the presence of these distinct ion classes. Based on the developed model, we derive microscopic CR and ETU parameters of CCR = 5.83 × 10–38 cm6 s–1, CETU1 = 0.93 × 10–40 cm6 s–1, and CETU2 = 7.81 × 10–40 cm6 s–1, and determine the laser quantum efficiency ...

  • Energy Transfer Processes in er3 doped and er3 pr3 codoped zblan glasses
    Physical Review B, 2000
    Co-Authors: P S Golding, T. A. King, Stuart D. Jackson, Markus Pollnau
    Abstract:

    We present a detailed characterization of Energy Transfer Processes in Er3+-doped and Er3+,Pr3+-codoped ZBLAN bulk glasses. For several Er3+ (0.25–8.75 mol%) and Pr3+ (0.25–1.55 mol%) concentrations, we investigate Energy Transfer upconversion (ETU) and cross relaxation in Er3+ as well as Energy Transfer (ET) from Er3+ to the Pr3+ codopant. The measured parameters of ETU from the Er3+ 4I13/2 and 4I11/2 levels are comparable to those of LiYF4:Er3+. ETU from 4I13/2, in particular, possesses a factor of 3 larger probability than ETU from 4I11/2. The parameters of ET from the Er3+ 4I13/2 and 4I11/2 levels to the Pr3+ codopant are larger than the corresponding ETU parameters. ET effectively quenches the 4I13/2 intrinsic lifetime of 9 ms down to 20 us for the highest Er3+ and Pr3+ concentrations investigated, and is more efficient than ET from 4I11/2, because the corresponding absorption transition in Pr3+ has a large oscillator strength and back Transfer is inhibited by fast multiphonon relaxation from the corresponding Pr3+ level. In both cases, the ET parameters depend on Er3+ concentration in a similar way as the ETU parameters but depend only weakly on Pr3+ concentration. This shows that Energy migration within the Er3+ 4I13/2 and 4I11/2 levels is fast. The presented results are important for the choice of the appropriate operational regime of the erbium 3-um fiber laser.

I A A Terra - One of the best experts on this subject based on the ideXlab platform.

  • analysis of Energy Transfer Processes in yb3 tb3 co doped low silica calcium aluminosilicate glasses
    Journal of Applied Physics, 2011
    Co-Authors: I A A Terra, L J Borrerogonzalez, L A O Nunes, Marcos Paulo Belancon, J H Rohling, M L Baesso, O L Malta
    Abstract:

    Energy Transfer Processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses were analyzed. Luminescence and time-resolved measurements were used to study upconversion Processes, such as Yb-Tb cooperative sensitization, Yb-Yb cooperative luminescence, and Yb-Tb cross relaxation. The quantum cross relaxation efficiency was evaluated as a function on the Yb3+ concentration, and the maximum estimated value was approximately 51%. In addition, the intensity of the upconversion luminescence from the Tb3+:5D4 level decreased by two orders of magnitude comparing the value at room temperature with that at 123 K. As a consequence, Yb-Yb cooperative luminescence around 500 nm became comparable with the intensity of upconversion from the Tb3+:5D4 level. Furthermore, a dependence of the upconversion kinetics luminescence on temperature was observed. The upconversion rise time was constant and equal to 65 μs for temperatures between 296 to 473 K and decreased from 65 to 19 μs, without variation in the de...

  • analysis of Energy Transfer Processes in yb3 tb3 co doped low silica calcium aluminosilicate glasses
    Journal of Applied Physics, 2011
    Co-Authors: I A A Terra, L J Borrerogonzalez, Marcos Paulo Belancon, J H Rohling, M L Baesso, Luiz Antonio De Oliveira Nunes, O L Malta
    Abstract:

    Energy Transfer Processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses were analyzed. Luminescence and time-resolved measurements were used to study upconversion Processes, such as Yb-Tb cooperative sensitization, Yb-Yb cooperative luminescence, and Yb-Tb cross relaxation. The quantum cross relaxation efficiency was evaluated as a function on the Yb3+ concentration, and the maximum estimated value was approximately 51%. In addition, the intensity of the upconversion luminescence from the Tb3+:5D4 level decreased by two orders of magnitude comparing the value at room temperature with that at 123 K. As a consequence, Yb-Yb cooperative luminescence around 500 nm became comparable with the intensity of upconversion from the Tb3+:5D4 level. Furthermore, a dependence of the upconversion kinetics luminescence on temperature was observed. The upconversion rise time was constant and equal to 65 μs for temperatures between 296 to 473 K and decreased from 65 to 19 μs, without variation in the decay part, when the temperature was lowered from 296 to 123 K. These results were explained by a phonon-assisted cooperative sensitization process for the population of the Tb3+:5D4 level.