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LiBa <sub/>4</sub> Ga <sub/>5</sub> Q <sub/>12</sub> (Q = S, Se): Noncentrosymmetric Metal Chalcogenides with a Cesium Chloride Topological Structure Displaying a Remarkable Laser Damage Threshold
摘要： The exploration of novel infrared nonlinear optical (IR NLO) materials with large second-harmonic generation (SHG) responses and wide band gaps has become very imperative recently. Herein we reported two noncentrosymmetric compounds, LiBa4Ga5Q12 (Q = S, Se), crystallizing in space group P421c (No. 114), which feature 3D frameworks built by a basic [Ga5Q16]17? windmill cluster and LiQ4 tetrahedra in a cesium chloride topological structure. Both compounds satisfy the desired balance between good SHG responses (～1.5× that of AgGaS2) and wide band gaps (3.43 and 2.44 eV) with remarkable laser damage thresholds (21× and 6× that of AgGaS2). The theoretical calculations uncover that the [Ga5Q16]17? cluster makes major contributions to the SHG e?ect in LiBa4Ga5Q12. In addition, the structure?performance relationship among all compounds in the I?II4?III5?VI12 system has been discussed systematically, which indicates that the introduction of the alkali metal lithium in the I site is bene?cial for the production of large band gaps. This work will be helpful in exploring novel IR NLO materials with special structures and comprehensive properties in the chalcogenide system.
关键词： chalcogenides,infrared nonlinear optical materials,laser damage thresholds,cesium chloride topological structure,second-harmonic generation
更新于2025-09-19 17:13:59
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Comparative analysis on the photoluminescence properties of Cs <sub/>2</sub> BF <sub/>6</sub> :Mn <sup>4+</sup> (B?=?Ge, Si, Zr, Ti) red phosphors for WLEDs
摘要： A series of Cs2BF6:Mn4+ (B = Ge, Si, Ti, Zr) red phosphors were synthesized by a precipitation‐cation exchange route. The phase purity, morphology, and constituent were characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties were investigated by photoluminescence (PL) spectra and high‐resolution PL. Temperature‐dependent PL examination at the range of both 273‐573 K and 10‐300 K was performed to investigate the emission mechanism of Mn4+ in these fluorides. The intensity for both zero‐phonon lines (ZPLs) and vibration coupled emission of Mn4+ in these four systems with different crystal structures was investigated systematically. These phosphors present bright red emission under blue light (467 nm) illumination, among which Cs2GeF6:0.1Mn4+ shows the highest emission intensity with ultrahigh quantum efficiency of 94%. The white light‐emitting diodes (WLEDs) fabricated with this sample, blue InGaN chips and commercial YAG:Ce3+ phosphor exhibited high luminous efficacy beyond 100 lm/w with high color rendering index (~88.6) and low color temperature (~3684 K).
关键词： phosphors,photoluminescence,optical materials/properties
更新于2025-09-19 17:13:59
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Cover Feature: Functional Metal Oxides in Perovskite Solar Cells (ChemPhysChem 20/2019)
摘要： The conflict between beneficial layered structure for performances and layered growth habits in KBe2BO3F2 (KBBF) always restricts its practical applications. A beryllium-free KBBF family member, Zn2BO3(OH), is explored to feature the same topological layer with KBBF by replacing [BeO3F]5? with [ZnO3(OH)]5? and excellent UV performances. It exhibits a second harmonic generation response of about 1.5 × KH2PO4 with the UV cutoff edge of 204 nm. The birefringence of Zn2BO3(OH) in the visible region is about 0.067, which is larger than those of commercial UV crystals LiB3O5, CsB3O5, and CsLiB6O10. Additionally, it has excellent thermal and water-resistant stabilities. Owing to the removal of interlayer cations, Zn2BO3(OH) shows better growth habits than KBBF while achieving the balance between beneficial layered structure and layer tendency.
关键词： borates,KBBF family,second harmonic generation,nonlinear optical materials,crystal growth habits
更新于2025-09-19 17:13:59
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Eu3+ co-doped Sr3Gd(PO4)3:Dy3+ phosphors: luminescence properties and color-tunable white-light emission for NUV-WLEDs
摘要： A series of Dy3+ and Eu3+ co-doped Sr3Gd(PO4)3 phosphors were synthesized by a high-temperature solid-state method. The crystal structure, optical band gap energy, luminescence properties, concentration quenching, energy transfer process and thermal stability were investigated. All the phosphors are pure eulytite-type Sr3Gd(PO4)3 in structure. Under different wavelengths’ excitation, the Sr3Gd(PO4)3:Dy3+, Eu3+ phosphors exhibit different emission intensities for Eu3+ and Dy3+. The color and correlated color temperature (CCT) can be tuned from cool white to warm white by adjusting excitation wavelengths and the doping concentration of Eu3+. Under the 351-nm excitation, the optimal Sr3Gd(PO4)3:0.03Dy3+, 0.085Eu3+ phosphor displays a warm white emission with CIE coordinate of (0.3987, 0.3613), CCT of 3409?K, internal quantum efficiency of 44.8% and activation energy of 0.1883?eV. These results suggest that single-phased white-emitting phosphors Sr3Gd(PO4)3:Dy3+, Eu3+ can be used in the near-ultraviolet light-emitting diodes.
关键词： Optical materials and properties,Luminescence,Energy transfer,Phosphors
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID) - Miramar Beach, FL, USA (2019.8.19-2019.8.21)] 2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID) - Quantum Yield Measurement of Organometallic Complexes using Double Pump Probe Technique
摘要： The abstract of the paper is not provided in the given text.
关键词： Nonlinear optics,optical nonlinearities in optical Materials,Nonlinear optical Material
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - The nonlinear optical properties of few-layer VSe <sub/>2</sub> nanosheets
摘要： Vanadium Diselenide (VSe2) has a high electrical conductivity owing to the electron delocalization of the vanadium lattice framework. Most of previous research has been focused on its electronic properties. The nonlinear optical properties of VSe2 have not been investigated yet. Herein, we prepared few-layer VSe2 nanoflakes by liquid phase exfoliation. Subsequently, we utilized Z-scan technique to study the nonlinear optical properties of few-layer VSe2 nanoflakes. And we prepared VSe2 based saturable absorbers (SA) and achieved passively mode-locked operation in Er-doped fiber laser. The results indicate that VSe2 nanosheets own remarkable nonlinear optical properties and could be employed as ideal saturable absorption materials in pulsed fiber lasers.
关键词： Mode-locked,Saturable absorbers,Vanadium Diselenide,Nonlinear optical materials
更新于2025-09-16 10:30:52
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The influence of PT-symmetric degree on extraordinary optical properties of one-dimensional periodic optical waveguide networks
摘要： In this paper, we design two kinds of one-dimensional (1D) equal-length two-segment-connected periodic triangular optical waveguide networks with different PT-symmetric degrees, one-dimensional PT-symmetric triangular optical waveguide network (1D PT-TOWN) and one-dimensional non-PT-symmetric triangular optical waveguide network (1D nPT-TOWN). It is found that no matter whether the network is PT-symmetric or non-PT-symmetric, as long as a PT-symmetric unit exists, both gain and loss photonic nonpropagation modes will be created and their frequencies are all the same. Consequently, ultrastrong extraordinary transmissions can be generated by two networks, which can arrive at 62.210× and 48.710× respectively. However, because the PT-symmetric degree of the former is higher than the latter, the transmission of the former is two orders of magnitude larger than the latter. Therefore, The PT-symmetric degree influences seriously on the photonic modes distribution and transmission of the network. Our research may deepen people's understanding of PT symmetry, which has potential application to the design of high-efficiency photon energy storage device, optical switches, optical amplifiers, and so on.
关键词： waveguides,optical materials,metamaterials
更新于2025-09-16 10:30:52
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Growth of 4-N,N-Dimethylamino-4'-N'-methyl-stilbazolium Tosylate (DAST) Organic Single Crystals Controlled by Oleic Acid
摘要： 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST) organic single crystals controlled by (Z)-Octadec-9-enoic acid (oleic acid, OA) was grown by a slow-cooling method. The as-grown DAST single crystals were systematically characterized by FTIR, X-ray diffraction, second harmonic generation, and UV-vis spectroscopy. Results indicate that addition of OA into the DAST solutions leads to the controlled growth of DAST single crystals and consequently, the crystal quality and optical properties can be modified. Particularly, the DAST crystals grown under the control of OA exhibit larger sizes, higher crystallinities, and better optical qualities with higher optical band gaps and lower defect density, compared with those grown in the absence of OA. These results are helpful for better understanding the controlled growth of DAST organic single crystals and modifying their properties for practical applications.
关键词： nonlinear optical materials,crystal growth,additives,DAST single crystals
更新于2025-09-16 10:30:52
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Silicon-Organic Hybrid Photonic Devices in a Photonic Integrated Circuit Technology
摘要： In this work, we present recent results on the hybrid integration of electro-optical organic materials in a photonic integrated circuit (PIC) technology. We review some of the identi?ed challenges regarding process compatibility and present experimental results on the integration of organic materials in a PIC technology using a 0.25 μm SiGe BiCMOS pilotline. Here, we are focusing on electro-optical applications toward high-speed modulators with ultra-low energy consumption.
关键词： photonic integrated circuit,high-speed modulators,electro-optical materials,silicon-organic hybrid,ultra-low energy consumption
更新于2025-09-16 10:30:52
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Yttrium oxide as a Q-switcher for the near-infrared erbium-doped fiber laser
摘要： Yttrium oxide (Y2O3) has been widely used in metal-reinforced composites, microelectronics, waveguide lasers, and high-temperature protective coatings because of its good physical and photoelectric properties. However, few studies have been done on the nonlinear optical applications of Y2O3 as saturable absorbers (SAs) in fiber lasers so far. Here, a passively Q-switched near-infrared fiber laser using Y2O3 as a Q-switching device is demonstrated. The optical nonlinear properties of the Y2O3 SA prepared by the magnetron sputtering method were measured by the twin-detector measurement technique, and the modulation depth of the proposed Y2O3 SA was found to be 46.43%. The achieved Q-switched laser delivers an average output power of 26 mW at 1530 nm with a pulse duration of 592.7 ns. To the best of our knowledge, this is the first report on the optical nonlinearity of Y2O3 as a Q-switcher for the near-infrared fiber laser, which may deepen the understanding of the optical nonlinear properties of Y2O3 and make inroads into the potential market of optical modulation and optoelectronic devices.
关键词： Q-switched laser,saturable,fiber lasers,absorbers,nonlinear optical materials
更新于2025-09-16 10:30:52