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Magnetic linear birefringence of light in Tb3Ga5O12
摘要： The spectra of the magnetic linear birefringence (MLB) in the terbium-gallium garnet TbGG (Tb3Ga5O12) have been studied within the visible spectral range for temperature T = 90 K. Analysis of the temperature and spectral dependences of MLB has made it possible to determine the “e?ective” frequencies of the allowed →f d electric dipolar transitions in rare-earth (RE) ions of Tb3+ ions responsible for the formation of quadratic magneto-optical e?ect in this garnet. The results of the performed magneto-optical experiments in TbGG have con?rmed the Akulov's relations (for the quadratic magnetic e?ects) arising from the phenomenological consideration of MLB for the values of Δn measured at the orientation of the external ?eld in the plane (110) along the main crystallographic directions of the garnet crystal. From analysis of the experimental data on MLB was obtained that for the TbGG MLB changes quadratically with the ?eld within the temperature range 90–300 K. At the same time with a decrease in temperature, its value grows inversely proportional to the square of temperature. A certain di?erence was also found in the “e?ective" frequencies of the allowed transitions in Tb3+ ions of the garnet, which is determined from the optical absorption spectra of TbGG on the one hand, and from the analysis of the spectral dependence of MLD on the other one. It has been assumed that this di?erence can be due to signi?cant distortions of the TbGG crystal lattice caused by this signi?cant magnetostriction at low temperatures, leading to the "mixing" of the 9D term states with the "optically resolved" states of the 7D term.
关键词： Terbium-gallium garnet,Akulov's relation,Magnetic linear birefringence
更新于2025-09-19 17:15:36
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Photoluminescence, conductivity and structural study of terbium doped ZnO films grown on different substrates
摘要： The effect of substrate material (Si, SiO2, Al2O3) on structural, optical and electrical properties of terbium doped ZnO films (Tb-ZnO) has been investigated by the X-ray diffraction, Raman scattering, atomic force microscopy, photoluminescence and infrared reflection methods. All films consist of micron size clusters of closely packed ZnO grains separated by deep trenches. The width of the trenches depends on the substrate material, being the largest in the Tb-ZnO/Al2O3 one. It is shown that the film on Al2O3 substrate contains the largest amount of extended and point defects. This film also demonstrates the highest intensity of Tb3+-related photoluminescence, while the film on Si substrate shows the lowest. On the contrary, the largest free carrier concentration evaluated from the infrared reflection spectra is found for Tb-ZnO/Si film and the lowest one is for the Tb-ZnO/Al2O3 film.
关键词： Luminescence, Raman spectroscopy,Doping,ZnO, terbium,Conductivity
更新于2025-09-19 17:15:36
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Luminescence varied by selective excitation in Eu3+,Tb3+-doped LiSrPO4 phosphors for W-LEDs applications
摘要： Tb3+ and Eu3+-doped LiSrPO4 (LSPO) were produced via a modified sol-gel route. Structural and optical characterization was performed by X-ray diffraction (XRD) and photoluminescence spectroscopy (PL), respectively. The results reveal that the presence of dopants has an effect on the LSPO structure. PL spectra of the LSPO:Tb, Eu (LSPOTE) phosphor consisted of major emission lines associated with 5D3,4-7FJ (J = 3, 4, 5 and 6) and 5D0-7FJ (J = 0, 1, 2, 3 and 4) transitions of Tb3+ and Eu3+ ions, respectively. A change in emission spectra was observed when the excitation wavelength was changed. Under middle-ultraviolet excitation (227 nm), the Tb3+ and Eu3+-doped LiSrPO4 phosphor exhibited white emission. The results suggest that the LiSr0.97PO4:Tb0.01,Eu0.02 phosphors prepared in the present work could be used in combination with AlGaN chips to fabricate white LEDs.
关键词： Terbium,Lithium strontium orthophosphate,Europium,White LEDs
更新于2025-09-16 10:30:52
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Solution Combustion Synthesis of ZrO 2 :Tb 3+ Nanophosphors Viable for WLEDs
摘要： Tb3+ doped Zirconium oxide (ZrO2) nanopowders were synthesized by solution combustion method using oxalyl di-hydrazide (ODH). The effect of dopant concentration on the crystal structure and photoluminescence properties of the nano phosphors were investigated. Band gap of the samples were obtained from Wood and Tauc plot. Scanning electron microscopy analysis reveals the formation of porous powders with large amount of voids. Room temperature photoluminescence shows visible luminescence of the phosphors under near UV excitation. The colour index of phosphors were calculated using CIE co-ordinates. These phosphors show bright green emission centered at 550 nm. The emission intensity increased with Tb3+ concentration up-to 5 mol% and decreased thereon. All these samples were emitting green colour having colour coordinates at (0.25,0.65). The colour purity of the samples reveals that these phosphors are promising candidates as green emitting phosphors in the tricolor GaN based white light emitting diodes.
关键词： Phosphors,Zirconia,Terbium,WLEDs,Photoluminescence
更新于2025-09-12 10:27:22
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Supramolecular structures of terbium( <scp>iii</scp> ) porphyrin double-decker complexes on a single-walled carbon nanotube surface
摘要： This work mainly reports the observation of novel supramolecular structures of TbIII-5,15-bisdodecylporphyrin (BDP, C12P) double-decker complexes on the surfaces of single-walled carbon nanotubes (SWNTs) performed by scanning tunneling microscopy under an ultra-high vacuum and low temperature, atomic force microscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and ultraviolet-visible spectroscopy. The molecules formed a well-ordered self-assembled helix-shaped array with regular periodicity on the tube surface. Additionally, some magnetic properties of the BDP-molecule as well as the resulting BDP-SWNT composites were investigated by superconducting quantum interference measurements. The molecule exhibits single-molecule magnetic (SMM) properties and the composite's magnetization increases almost linearly with decreasing temperature which is possibly due to the coupling between porphyrin molecules and SWNTs. Consequently, this may enable the development of more advanced spintronic devices based on porphyrin-nanocarbon composites.
关键词： Scanning tunneling microscopy,Magnetic properties,Supramolecular structures,Single-walled carbon nanotube,Atomic force microscopy,Terbium(III) porphyrin
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Diode-Pumped Visible Laser Operation of Tb <sup>3+</sup> :LiLuF <sub/>4</sub>
摘要： Trivalent terbium-doped materials have been attracting the attention of the scientific community due to the capacity of Tb3+ to emit in the visible range. Efficient laser operation at green and yellow wavelengths has been demonstrated previously while laser operation in the orange and red ranges is not expected due to detrimental excited state absorption (ESA) processes [1-4]. Previous research on laser operation of Tb3+ doped materials was performed under pumping with frequency doubled optically pumped semiconductor laser (2ω-OPSL). These blue emitting pump sources exhibit an excellent beam quality at output powers up to 5 W, but they are complex, bulky, and expensive, and thus not well suited for power scaling. Diode-pumping presents a cost-efficient alternative with potential for power scaling and miniaturization. The availability of InGaN-based blue laser diodes makes it possible to match the peak absorption wavelength of the 7F6→5D4 transition of Tb3+ ions around 488 nm. Here, we present to the best of our knowledge, the first diode-pumped Tb3+ based laser. Under 200 mW of pump power at 488.3 nm, the laser operates in continuous wave (cw) at 542 or 544 nm with a maximum slope efficiency of 53% and up to 44 mW of output power.
关键词： visible laser,diode-pumped,Tb3+:LiLuF4,terbium-doped materials
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Temperature Dependence of Magnetic Permeability and Optical Polarization Rotation of Gallium-Terbium Garnet Crystals
摘要： Faraday isolators (IF) are widely used in high-power fiber lasers in order to eliminate the detrimental influence of back reflections during the laser operation. One of the most widespread materials used for IF is a gallium-terbium garnet (TGG) crystal due to its appropriate magneto-optical properties. However, heating of magneto-optical crystals due to absorption of laser radiation deteriorates IF properties. Non-uniform heating leads to mechanical stresses and, therefore, to non-uniform polarization distortions. Values of optical absorption coefficients of TGG greatly depend on a crystal growth technology. Determination of the temperature dependence of optical absorption of TGG crystal was also one of the goals of this research. Optical absorption coefficient of cylindrical TGG sample (diameter d = 0.4 cm, length l = 2 cm) at 1060 nm wavelength was measured using laser calorimetry, i.e. by measuring the temperature of the crystal heated by transmitting laser radiation. Dependence of the crystal heating on transmitted optical power was 1.1±0.1 K/W. Absorption coefficient was calculated by solving the heat balance equation. Its value has increased from 1.6*10-3 cm-1 to 1.9*10-3 cm-1 as a result of heating from 22 oC to 43 oC. Also the contribution of the temperature dependent magnetic permeability μ(T) of TGG on the polarization rotation angle β was experimentally estimated. Temperature dependence of the magnetic permeability of TGG crystal was experimentally measured using resonant impedance spectroscopy. The value of TGG magnetic permeability was about 1.008 at room temperature (20 oC) and has decreased by Δμ = ? 1.2*10-4 when the crystal was heated to 80 oC. The temperature dependences of the polarization axis rotation angle change Δβ were measured in the cases of the uniform heating of TGG sample in a furnace and its nonuniform heating by transmitting linearly polarized laser radiation up to 30 W of optical power (1064 nm wavelength, 2 mm beam diameter). Applied magnetic field strength was 0,4 T, full angle of polarization axis rotation – 17,5 deg. Taking into account the measurement errors Δβ(T) ? (5 ± 0.25)*10-2 deg/ oC for both cases. It should be noticed that narrower laser beams can lead to greater differences due to the presence of larger temperature gradients. Consideration of the measurement results of μ(T) and β(T) revealed that the contribution of magnetic permeability variation with temperature to an overall polarization rotation angle change is almost 90 times lower than the thermally induced change of Verdet constant. Nevertheless, μ(T) influence should be considered if a precise control of polarization axis angle is required.
关键词： gallium-terbium garnet,Faraday isolators,TGG,magnetic permeability,temperature dependence,optical polarization rotation
更新于2025-09-11 14:15:04
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - The Measurement System for the Giant Magnetostriction Material Based on the Laser Displacement Method
摘要： A measurement system is built to measure the magnetostrictive strain of giant magnetostrictionmaterial. The system based on the laser displacement method includes the dual laser devices, the electromagnet and the control unit. The system has the characteristics of non-contact, overall and accurate measurement. The electromagnet is used to generate the magnetic field of 5000 Oe. The magnetostrictive-strain curve of Terbium-dysprosium-iron (Terfenol-D) samples are measured. The uncertainty of magnetostrictive strain is less than 2.5% (k=2).
关键词： Terbium-dysprosium-iron,Giant magnetotrictive material,Laser displacement method,Non-contact,Terfenol-D,measurement,strain
更新于2025-09-11 14:15:04
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Fluorescence Properties of Tb-Doped ZnO Porous Network Thin Film Grown on Monocrystalline Silicon Substrate
摘要： This research presents a new perspective on optical biosensors based on zinc oxide nanoparticles. The widely known and successfully applied nanostructured material is modified by the dopant - the green phosphor Terbium, which embedded in the structure of zinc oxide and makes a significant contribution to the fluorescent response of the material in both the UV and visible spectral regions. The effect of various dopant concentrations on the fluorescence of nanostructures was studied; the nanostructures were examined by SEM.
关键词： fluorescence,biosensors,nanostructures,zinc oxide,terbium
更新于2025-09-10 09:29:36
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Red- and green-emitting nano-clay materials doped with Eu <sup>3+</sup> and/or Tb <sup>3+</sup>
摘要： Trivalent europium (Eu3+) and terbium (Tb3+) ions are important activator centers used in different host lattices to produce red and green emitting materials. The current work shows the design of new clay minerals to act as host lattices for rare earth (RE) ions. Based on the hectorite structure, nano‐chlorohectorites and nano‐fluorohectorites were developed by replacing the OH? present in the hectorite structure with Cl? or F?, thus avoiding the luminescence quenching expected due to the OH? groups. The produced matrices were characterized through X‐ray powder diffraction (XPD), transmission electron microscopy (TEM), FT‐IR, 29Si MAS (magic angle spinning) NMR, nitrogen sorption, thermogravimetry‐differential scanning calorimetry (TGA‐DSC) and luminescence measurements, indicating all good features expected from a host lattice for RE ions. The nano‐clay materials were successfully doped with Eu3+ and/or Tb3+ to yield materials preserving the hectorite crystal structure and showing the related luminescence emissions. Thus, the present work shows that efficient RE3+ luminescence can be obtained from clays without the use of organic ‘antenna’ molecules.
关键词： fluorohectorite,europium,host lattices,terbium,chlorohectorite
更新于2025-09-09 09:28:46