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Growth, optical, mechanical and nonlinear optical properties of Furfurylaminium 2-chloro-5-nitrobenzoate single crystal
摘要： The furfurylaminium 2-chloro-5-nitrobenzoate (FC) is a modernized organic material possessing enhanced order three nonlinearity. The crystals of FC of dimensions 17 × 4 × 2 mm3 were yielded on slow evaporation with the usage of ethanol-water mixed solvent (1:1). The precise peaks in powder XRD analysis reveal the crystalline property of the compound. The lattice parameters was estimated (a = 11.77 ± 0.012 ?, b = 6.84 ± 0.012 ? and c = 16.33 ± 0.028 ? and volume = 1342 ?3) from powder XRD using XRDA software. The FC crystal corresponds to the system of monoclinic with the space group P21/c. The UV-visible spectrum of FC crystal sample furnishes the lower cut off wavelength (325 nm) and the band gap (3.57 eV) for FC crystal. The dispersion factors Eo and Ed was calculated to be 4.24 eV and 15.20 eV respectively from Wemple and Di Domenico single oscillator model. Using these values, the oscillator strength value was calculated to be 64.5134 (eV) 2 and the moments of optical spectra was estimated to be M -1 = 3.580 (eV) 2 and M -3= 0.198 (eV) 2. The optical conductivity (σ) value of FC crystal at 532 nm was found out to be 0.21 ×1010 s-1. A red emission peak at 691 nm was obtained in photoluminescence spectra when the FC sample was excited at 325 nm. Single shot LDT value for FC crystal was calculated to be 14.40 GW/ cm2. The third order optical susceptibility (χ(3)) of the molecule was enumerated as 4.02 ×10-6 esu from Z-scan technique and the second order hyperpolarizability (γ) value is calculated to be 2.64 × 10-35 esu. The coupling factor (ρ*) is estimated to be 0.047, on utilizing the calculated values of (Re χ(3) = 0.19 × 10-6 esu) and (Im χ(3) =0.19 × 10-6 esu) from Z scan technique. The specific heat capacity (Cp) at 50°C was calculated as 1.5810 (Jg-1 K-1) and thermal diffusivity (α) as 1.750 ×10-6 m2/s. Thus using α the thermo-optic coefficient was deliberated to be 5.34 × 10-6 K-1. The maximum output power of FC indicates its optical limiting behaviour.
关键词： third order susceptibility,optical limiting,Solution growth,Optical materials,Z-scan
更新于2025-09-23 15:22:29
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Phase formations and red-luminescence enhancement of Eu3+-activated NaBaY(BO3)2 phosphors
摘要： Eu3+-activated Na1-xKxBaY(BO3)2 (x = 0.1–1.0) phosphor was prepared via facile solid-state reaction ceramic method. The structural Rietveld refinements were completed to confirm the phase formations. The luminescence properties were reported such as photoluminescence excitation (PLE) and emission (PL) spectra, decay lifetime, experimental quantum efficiency (QE) and thermal stabilities. The phase formations and the luminescence properties of the phosphors have a dependence on the K+-substituting for Na+ in the lattices. The results showed that Na1-xKxBaY0.5Eu0.5(BO3)2 (x = 0.1–1.0) phosphors formed the trigonal NaBaY(BO3)2 single phase (Na-phase, space-group of R-3, No.148). Increasing the K+-substituting for Na+ (x ≤ 0.3) induced the appearance of KBaY(BO3)2 phase (K-phase, space-group of R-3 m, No. 166) together with the Na-phase (0.3 < x < 0.6). Heavily K-substituted samples crystallized into a single K-phase. Luminescence characteristics of Eu3+ ions were investigated on the evolution of the substituting-level. It was observed that the phosphors presented the improved emission intensity and thermal stability in the mixed phases.
关键词： Phase transitions,Photoluminescence,Optical materials and properties,Europium,Borates
更新于2025-09-23 15:22:29
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Synthesis of High Performance Cyclic Olefin Polymers (COPs) with Ester Group via Ring-Opening Metathesis Polymerization
摘要： Novel ester group functionalized cyclic olefin polymers (COPs) with high glass transition temperature, high transparency, good mechanical performance and excellent film forming ability have been achieved in this work via efficient ring-opening metathesis copolymerization of exo-1,4,4a,9,9a,10-hexahydro-9,10(1′,2′)-benzeno-l,4-methanoanthracene (HBM) and comonomers (5-norbornene-2-yl methylacetate (NMA), 5-norbornene-2-yl methyl 2-ethylhexanoate (NME) or 5-norbornene-2-yl methyldodecanoate (NMD)) utilizing the Grubbs first generation catalyst, Ru(CHPh)(Cl)2(PCy3)2 (Cy = cyclohexyl, G1), followed by hydrogenation of double bonds in the main chain. The fully hydrogenated copolymers were characterized by nuclear magnetic resonance, FT-IR spectroscopy analysis, gel permeation chromatography, and thermo gravimetric analysis. Differential scanning calorimetry curves showed that the glass transition temperatures (Tg) linearly decreased with the increasing of comonomers content, which was easily controlled by changing feed ratios of HBM and comonomers. Static water contact angles tests indicate that hydrophilicity of copolymers can also be modulated by changing the comonomers incorporation. Additionally, the mechanical performances of copolymers were also investigated.
关键词： dimensional stability,optical materials,COPs (cyclic olefin polymers),ROMP (ring-opening metathesis polymerization),hydrophilicity
更新于2025-09-23 15:22:29
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Enhanced optical properties of YAG:Ce yellow phosphor by modification with gold nanoparticles
摘要： In this paper methods of synthesis and characterization of cerium doped yttrium aluminum garnet (YAG:Ce) and the improvement of properties by in situ modification using gold nanoparticles are presented. YAG:Ce phosphor was obtained by cations co-precipitation followed by thermal treatment at 1000 °C, while for the development of the Au-YAG:Ce nanocomposites, the Turkevich method was used. The quality of the phosphor particles and composite has been structurally, morphologically and optically studied. It has been emphasized the obtaining of high purity phosphor and maintenance of the YAG:Ce garnet structure after modifying the phosphor surface with gold nanoparticles. Also, the use of gold nanoparticles has led to improvements in optical and morphological properties as a result of lowering the agglomeration trend. Improvement of optical properties makes possible the use of Au-YAG:Ce composite thus developing low energy light sources and with high performance.
关键词： YAG:Ce,Au-YAG:Ce composite,Optical materials,Phosphor
更新于2025-09-23 15:22:29
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Effect of codoping Ce <sup>3+</sup> on the luminescence properties of Sr <sub/>9</sub> Mg <sub/>1.5</sub> (PO <sub/>4</sub> ) <sub/>7</sub> :Eu <sup>2+</sup> orange-yellow phosphor
摘要： Sr9Mg1.5(PO4)7:Eu2+ has recently been reported as a promising blue light-excited orange-yellow phosphor that can be used in white LED device. Here, Ce3+-codoping is found to be an effective strategy to improve the luminescence performance of Sr9Mg1.5(PO4)7:Eu2+ phosphor. The coexistence of Eu2+ and Eu3+ ions has been verified via photoluminescence spectral analysis. The reduction of Eu3+ to Eu2+ in Sr9Mg1.5(PO4)7 lattice cannot be completed in a reducing atmosphere, but can be promoted through codoping with Ce3+ ions to a great extent, which finally increase the effective concentration of Eu2+ in the crystal lattice. The Eu3+–Eu2+ reduction mechanism is analyzed using a charge compensation model. This work not only achieves enhanced luminescence of the Sr9Mg1.5(PO4)7:Eu2+ phosphor by codoping with Ce3+ ions, but also provides new insights into the design of Ce3+/Eu2+ codoped luminescent materials.
关键词： optical materials,defects,doping,LED,europium
更新于2025-09-23 15:22:29
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Label-free nanoparticle sensors based on a triple-layer-coated microsphere structure
摘要： We present a design for a sensitive, label-free nanoparticle sensor based on triple-layer-coated microsphere resonators. The surfaces of the microsphere structure are coated with three layers that have high, low, and high refractive indexes from inside to outside, respectively. We theoretically and numerically investigate two cladding modes, we call the inner mode and outer mode. The resonance wavelengths of the two modes are used to detect the resonance wavelength shift caused by a single-nanoparticle. Numerical calculation suggests that if we change the thickness of the middle layer, the device offers another degree of freedom to obtain higher detection sensitivity. We build a model to accurately describe a nanoparticle close to the microsphere. The method for the sensors may promote the design of biosensing applications.
关键词： Optical materials and properties,Sensors,Simulation and modelling,Microstructure
更新于2025-09-23 15:22:29
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Electronic, Optical and Elastic Properties of Cu2CdGeSe4: A First-Principles Study
摘要： Using the augmented plane wave + local orbitals method with different approximation functionals, we investigate systematically the electronic, optical and elastic properties of stannite-type Cu2CdGeSe4. Among different approximation functionals, the modi?ed Becke–Johnson (mBJ) potential with Hubbard-corrected parameter U (mBJ + U) gives the most reliable results on the electronic properties of Cu2CdGeSe4 in comparison with the experimental data. Elastic modulus, elastic constants and the Poisson’s ratio of Cu2CdGeSe4 were calculated using the Elastic software package. Optical properties such as wide spectrum of absorbed photon energy, namely 1.3–27.2 eV, high absorption coef?cient (above 104 cm?1) and optical anisotropy suggest the application of Cu2CdGeSe4 in solar cells.
关键词： electronic structure,optical properties,Optical materials,elastic properties,ab initio calculations
更新于2025-09-23 15:21:21
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A monolithic on-chip magneto-optical isolator with 3 dB insertion loss and 40 dB isolation ratio
摘要： On-chip optical isolators constitute an essential building block for photonic integrated circuits (PICs). Here we experimentally demonstrated a magneto-optical isolator monolithically integrated on silicon featuring 3 dB insertion loss and 40 dB isolation ratio, both of which represent significant improvements over state-of-the-art. The isolator is also fully passive and operates under a simple unidirectional magnetization scheme. Such superior performance is enabled through a three-way combination of a strip-loaded waveguide design, a compositionally optimized chalcogenide glass as the light guiding medium, and low-loss taper structures created via gray-scale lithographic processing. The device represents an important step towards a practical solution for on-chip isolation in PICs.
关键词： Integrated optics devices,Magneto-optical materials,Chalcogenide glass,Resonators,Grayscale-lithography,Isolators
更新于2025-09-23 15:21:21
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Pb <sub/>2</sub> GaF <sub/>2</sub> (SeO <sub/>3</sub> ) <sub/>2</sub> Cl: Band Engineering Strategy by Aliovalent Substitution for Enlarging Bandgap while Keeping Strong Second Harmonic Generation Response
摘要： Wide bandgap and strong second-order generation (SHG) effect are two crucial but contradictory conditions for practical nonlinear optical (NLO) materials. Herein, a new NLO crystal Pb2GaF2(SeO3)2Cl (I) containing novel functional (GaO3F3)6? octahedra is designed and synthesized by a rational band engineering strategy with aliovalent substitution. Benefiting from the removal of transition metal cations and the introduction of bridged F anions, I exhibits the widest bandgap among all reported phase-matchable NLO selenites. Meanwhile, a strong SHG response more than 4.5 times of KH2PO4 (KDP) is maintained. The dominate role of the (GaO3F3)6? groups to the enlarged bandgap in I are elucidated by first-principles studies.
关键词： aliovalent substitution,second harmonic generation,nonlinear optical materials,selenites,band engineering
更新于2025-09-23 15:21:21
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EuF2-based crystals as media for high-power mid-infrared Faraday isolators
摘要： This letter presents the investigation of spectral, magneto-optical and thermo-optical characteristics of cubic EuF2 +x solid solution crystals. The dispersion of the Verdet constant measured in the wavelength range of 532–1940 nm demonstrates that such crystals can be used for creating Faraday isolators for the wavelength of ~2 μm. The optical anisotropy parameter of EuF2+x crystals is negative, which means that there exists a dedicated orientation of the crystallographic axes at which thermally induced depolarization may be reduced substantially. The performed research shows that an EuF2 crystal is highly promising for the development of Faraday isolators for high-power mid-IR lasers.
关键词： Thermo-optic effects,Magneto-optical materials,Faraday effect
更新于2025-09-23 15:21:21