- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Dopant and excitation wavelength dependent color tunability in Dy3+ and Eu3+ doped CaBi2B2O7 phosphors for NUV warm white LEDs
摘要： Dy3+ was introduced into CaBi2B2O7 by high temperature solid state reactions and it was proved to locate at the Bi3+ site by powder X-ray di?raction. Dy3+ emits a bluish white light e?ciently both under 349 and 388 nm excitation, and the later one is important to the application for near ultra violet (NUV) WLEDs. Eu3+ was co-doped to tune the emitting color to warm white. Bene?tting from the Dy3+ to Eu3+ energy transfer, the natural white emission with CIE coordinate of (0.34, 0.36) and CCT of 5095 K was achieved for Ca(Bi0.88Dy0.05Eu0.07)2B2O7 under the 349 nm excitation. Importantly, both the warm-white light of 3248 K (λex =380 nm) and natural white of 5200 K (λex =386 nm) can be obtained by varying the excitation wavelength for Ca(Bi0.92Dy0.05Eu0.03)2B2O7. These preliminary results suggest the potential of Dy3+ and Eu3+ co-doped CaBi2B2O7 in the application for NUV warm white LEDs.
关键词： C. X-ray di?raction,D. Phosphors,A. Inorganic compounds,B. Luminescence,A. Optical materials
更新于2025-09-16 10:30:52
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Double line waveguide amplifiers written by femtosecond laser irradiation in rare-earth doped germanate glasses
摘要： We report the production of active double waveguides in Er/Yb doped GeO2-PbO glasses, by direct femtosecond laser writing. The glasses were produced using the melt-quenching technique and the active waveguides were written using 30 fs laser pulses, at 800 nm, with writing speed of 0.06 mm/sec and pulse energy of 32 μJ. The photo-induced negative refractive index change was of -7.4x10-3. The Er/Yb doped sample showed a relative gain (signal enhancement of 7.5 dB/cm, for 105 mW of 980 nm pump power. The relative gain compensates both, the propagation losses and the absorption losses, and a positive maximum internal gain of 4.6 dB/cm can be obtained at the signal wavelength of 1550 nm. The results obtained in present work demonstrate that Er/Yb glasses are promising materials for the fabrication of integrated amplifiers, lossless components and lasers based on germanate glasses.
关键词： Optical materials,Laser processing,Optical spectroscopy,Amorphous materials
更新于2025-09-12 10:27:22
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Direct observation and simultaneous use of linear and quadratic electro-optical effects
摘要： We report on the direct observation and simultaneous use of the linear and quadratic electro-optical effect and propose a method by which higher-order susceptibilities of electro-optical materials can be determined. The evaluation is based on the separation of the second- and third-order susceptibilities and the experimental technique uses a slot waveguide ring resonator fabricated in an integrated photonic circuit technology, which is embedded by a guest-host polymer system consisting of the azobenzene dye disperse red 1 in a poly(methyl methacrylate) matrix as active electro-optical material. The contribution of both effects on the electro-optical response under the influence of static and time-varying electrical fields is investigated. We show that the quadratic electro-optical effect has a significant influence on the overall electro-optical response even with acentric molecular orientated molecules. Our findings have important implications for developing electro-optical devices based on polymer-filled slot waveguides and give rise to advanced photonic circuits.
关键词： higher-order susceptibilities,electro-optical materials,quadratic electro-optical effect,slot waveguide,ring resonator,linear electro-optical effect
更新于2025-09-12 10:27:22
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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) - Characterization of the Verdet Constant of Dy <sub/>2</sub> O <sub/>3</sub> Ceramics in the Two-Micron Spectral Range
摘要： High-power solid-state mid-IR lasers are being actively developed, as they possess the key properties for a vast number of technological applications [1] (e. g. lidar, gas sensing, or pump sources optical parametric oscillators) and are in a high demand for basic research as well [2]. These potentialities have recently led to intensive investigations of new mid-IR laser gain media [3,4] and other optical elements. One of the key components under investigation is an optical isolator (OI), a magneto-optical device enabling safe operation of a laser by preventing harmful back-reflections into the laser cavity. The development of high-power OIs is particularly challenging due to the severe thermal effects which arise because of the relatively high absorption of the currently available magneto-optical elements. Therefore, a lot of scientific effort is being put into the research of novel magneto-optical materials with the desired properties: high Verdet constant, low absorption and excellent thermal properties. All of these properties enable a reduction of the heat generated in the magneto-optical element. A large number of new magneto-optical materials for high-power OIs have been reported in the recent years. The vast majority of these reports targeted materials suitable for the wavelengths around 1 μm (corresponding to the neodymium and ytterbium doped gain media) in the task to find a better alternative to the most commonly used magneto-optical material for this spectral range – the terbium gallium garnet (TGG) [5]. In this manner, materials based on highly magnetically active rare-earth ions (e. g. Ce3+ [6], Tb3+ [7] or Ho3+ [8]) have been established as a possible next generation of magneto-optical materials for the visible and near-IR OIs. Some of these materials possess local transparency windows in the mid-IR as well, however, reports dealing with their magneto-optical characteristics in this region (or reports of any other suitable materials) were so far very rare. Nevertheless, Verdet constants of CeF3 crystal [9], DyxY0.95-xLa0.05O3 ceramics (with variable doping X = 0.7 – 0.9) [10] and EuF2 crystal [11] have been recently reported at the wavelength of ~1.94 μm, having ~7, ~10 - 14, and ~12 rad/Tm respectfully. We present broadband experimental characterizations of the Verdet constant of three novel material samples of Dy2O3-based ceramics in a broad spectral range 0.6 – 2.4 μm with the relative error of the measurement ~5%. An analytical approximation of the data is a challenging task due to the multiple resonances and absorption bands of Dy3+ ions within the measured range and is currently under investigation. The obtained values for the Verdet constant at 1.94 μm were 17.8, 22.2 and 26.8 rad/Tm predicting a high potential for Dy2O3 ceramics utilization in a high-power mid-IR OIs. The measured transmittances of our samples at 1.94 μm were equal to 54%, 72% and 76%.
关键词： mid-IR lasers,optical isolators,magneto-optical materials,Dy2O3 ceramics,Verdet constant
更新于2025-09-12 10:27:22
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Eu3+-doped NaYGeO4: A novel red-emitting phosphors for ultraviolet or blue chips excited white LEDs
摘要： A novel red-emitting phosphor NaYGeO4: Eu3+ has been prepared by a high temperature solid state method. All the Eu3+ ions are completely dissolved in the NaYGeO4 host without changing its crystal structure. Under 315 nm host excitation or 464 nm 7F0→5D2 excitation, the phosphor NaYGeO4: Eu3+ presents red emission with the strongest peak at 613 nm. The concentration quenching and luminescence mechanism are also investigated. The optimal NaYGeO4: 0.05Eu3+ phosphor displays high internal quantum efficiency, excellent thermal stability with the activation energy (?E) of 0.2716 eV. The color emission can be tuned by changing the Eu3+ concentration. The phosphor presents a great potential application for ultraviolet or blue excited white LED.
关键词： Optical materials and properties,Thermal stability,Luminescence,Red phosphor
更新于2025-09-12 10:27:22
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Luminescence properties of Sm3+ and Dy3+ co-doped BaY2ZnO5 phosphor for white LED
摘要： Single-phased warm-white-emitting BaY2ZnO5:Dy3+, Sm3+ phosphors were synthesized by a high-temperature solid state reaction method. The crystal structure, luminescence properties, decay lifetimes, thermal stability and internal quantum efficiency (IQE) were investigated. Under 354 nm excitation, the emission spectrum exhibits the characteristic transitions of Sm3+ and Dy3+ and energy transfer mechanism are determined to be the dipole-dipole interactions. Due to the energy transfer from Dy3+ to Sm3+, the color tones and correlated color temperature (CCT) can be changed from near cool-white to warm-white when adjusting Sm3+ concentrations. The optimal BaY2ZnO5: 0.14Dy3+, 0.04Sm3+ emits warm-white light with CIE coordinates of (0.404, 0.367), low CCT of 3337 K, activation energy of 0.2389 eV and IQE of 61.5%, making it as a promising candidate white-emitting phosphor for LEDs application.
关键词： Phosphors,Luminescence,Optical materials and properties,Energy transfer
更新于2025-09-12 10:27:22
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Luminescence properties of new red-emitting phosphor Li2Al2Si3O10:Eu3+ for near UV-based white LED
摘要： Eu3t doped Li2Al2Si3O10 red phosphor was synthesized by the conventional high-temperature solid-state method. The crystal structure, morphology, luminescence properties, thermal stability and quantum efficiency were characterized. The powders show average particle size of 8 μm. The optimum Eu3t dopant concentration is 0.02 in Li2Al2Si3O10 host lattice. Luminescence quenching is attributed to electric dipole–dipole interaction and impurities. The emission intensity of the 5D0 → 7F2 transition (615 nm) is dominant upon the strongest excitation at 394 nm (7F0 → 5L6 transition). The Li2Al2Si3O10: 0.02Eu3t phosphor can be excited by near-ultraviolet (n-UV) light and exhibits red emission with the CIE chromaticity coordinates of (0.6389, 0.3488) and color purity as high as 93%. The Li2Al2Si3O10: 0.02Eu3t phosphor also possesses good thermal stability with quenching energy barrier of 1803 cm?1. The fluorescence lifetime and quantum efficiency are 0.388 ms and 31.5%, respectively. The results suggest that the red phosphor Li2Al2Si3O10:Eu3t can be used for n-UV excited white LEDs.
关键词： Phosphors,Luminescence,Optical materials and properties
更新于2025-09-12 10:27:22
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AlPO <sub/>4</sub> in Silica Glass Optical Fibers: Deduction of Additional Material Properties
摘要： A silica clad optical ?ber with a core comprised of SiO2, P2O5, Al2O3, and AlPO4 is analyzed in order to determine the impact of AlPO4 when added to silica. A chromatic dispersion curve is presented, from which the nonlinear refractive index is estimated to be similar to that of silica. When doped into SiO2, AlPO4 decreases the thermo-optic coef?cient (slightly), decreases the acoustic velocity, broadens the Brillouin spectral width through increased viscoelastic damping, and reduces the strength of the dependence of Brillouin frequency on temperature. Findings herein indicate that AlPO4 has a near-zero value of p12. It also is found that the ?ber does not have complete AlPO4 formation, with some P2O5 formation in Al2O3-rich regions of the ?ber. Given the relevance of AlPO4 to high power active ?ber technology, the presented data can be used for designing ?bers with enhanced performance characteristics, such as those with elevated threshold for the onset of stimulated Brillouin scattering.
关键词： Fiber optics,phosphorus,aluminum,?ber lasers,?ber nonlinear optics,optical materials,optical ?ber testing,glass
更新于2025-09-11 14:15:04
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A red-emitting phosphor K2[MoO2F4]?H2O:Mn4+ for warm white light-emitting diodes with a high color rendering index
摘要： A red-emitting phosphor K2[MoO2F4]?H2O:Mn4+ (denoted as KMOF:Mn4+) was designed and synthesized by a simple precipitation method, and its structure and luminescence properties were studied in details. The as-prepared KMOF:Mn4+ phosphors show broad excitation band in the blue-light region. The as-optimized phosphor KMOF:Mn4+ (3.28 mol%) has the strongest red-emission with high internal quantum efficiency of 86.5 % among these samples with different contents of Mn4+. Meanwhile, this sample is of the high thermal stability of luminescence. One white light-emitting diode (w-LED) was fabricated by coating KMOF:Mn4+ (3.28 mol%) and Y3Al5O12:Ce3+ on a GaN chip. This w-LED can emit intense warm white-light and show excellent photoelectric performances with a high color rendering index of 94, a low correlated color temperature of 3945 K, and the high luminous efficiency of 150.1 lm/W. Hence, KMOF:Mn4+ (3.28 mol%) could be a promising red phosphor for w-LEDs.
关键词： A. Optical materials,B. Fluorides,D. Phosphors,C. Luminescent properties
更新于2025-09-11 14:15:04
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Mode-Locked Er-Doped Fiber Laser by Using MoS2/SiO2 Saturable Absorber
摘要： The two-dimensional (2D) layered material MoS2 has attracted numerous attentions for electronics and optoelectronics applications. In this work, a novel type of MoS2-doped sol-gel glass composite material is prepared. The nonlinear optical properties of prepared MoS2/SiO2 composite material are measured with modulation depth (ΔT) of 3.5% and saturable intensity (Isat) of 20.15 MW/cm2. The optical damage threshold is 3.46 J/cm2. Using the MoS2/SiO2 composite material as saturable absorber (SA), a passive mode-locked Er-doped fiber (EDF) laser is realized. Stable conventional soliton mode-locking pulses are successfully generated with a pulse width of 780 fs at the pump power of 90 mW. In the pump power range of 100–600 mW, another stable mode-locking operation is obtained. The pulse width is 1.21 ps and the maximum output power is 5.11 mW. The results indicate that MoS2/SiO2 composite materials could offer a new way for optical applications.
关键词： Nonlinear optical materials,Saturable absorbers,Transition metal dichalcogenides
更新于2025-09-11 14:15:04