- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Second-Harmonic Generation from a Quantum Emitter Coupled to a Metallic Nanoantenna
摘要： We use time-dependent density functional theory and a semiclassical model to study second-harmonic generation in a system comprising a quantum emitter and a spherical metallic nanoparticle, where the transition frequency of the quantum emitter is set resonant with the second harmonic of the incident frequency. The quantum emitter is shown to enable strong second-harmonic generation, which is otherwise forbidden because of symmetry constraints. The time-dependent density functional theory calculations allow to identify the main mechanism driving this nonlinear effect, where the quantum emitter plays the role of an optical resonator that experiences the nonlinear near fields generated by the metallic nanoantenna located nearby. The influence of the intrinsic properties of the quantum emitter and the nanoantenna, together with the relative position of both in the coupled system allows for a high degree of control of the nonlinear light emission. The main effects and contributions to this nonlinear process can be correctly captured by a semiclassical description developed in this work.
关键词： quantum emitter,plasmonics,nonlinear optical response,Second-harmonic generation,electromagnetic coupling
更新于2025-09-23 15:19:57
-
Enhanced Broadband and Harmonic Upconversion from Coupled Semiconductor and Metal Nanoparticle Films
摘要： The enhancement of the nonlinear optical properties of hybrid nanoparticle ?lms by coupling between metallic and plasmonic semiconducting nanoparticles is shown. A heterostructure comprising CuS and Au nanoparticle ?lms separated by a thin layer of insulating ligands enhanced the yield of second-harmonic light by a factor of 3.3 compared with the sum of the constituent nanoparticles on their own. Heterostructures were fabricated with scalable solution-processing techniques that can create devices of arbitrary geometry. In addition to harmonic generation, the multiple-photon photoluminescence response of Au, CuS, and heterostructured ?lms is also explored.
关键词： plasmon,heterostructure,copper sul?de nanoparticle,second-harmonic generation,gold nanoparticle,multiphoton photoluminescence,nonlinear optical material
更新于2025-09-23 15:19:57
-
Enhancement of nonlinear optical and thermal properties of polyurethanes by modifying the chromophores with fused heterocyclic and pyrimidine rings
摘要： This article describes the synthesis of substituted triazolo[3,4-b]-thiadiazole heterocycles based nonlinear optical (NLO) responsive chromophores. To enhance the NLO properties of the chromophores, the pyrimidine ring was introduced with an appropriate π-bonding. With these chromophores, different series of polyurethanes were prepared by condensation with tolylene-2,4-diisocyanate and 3,30-dimethoxy-4,40-biphenylene diisocyanate. The structure of the resulting chromophores and polyurethanes was confirmed using Fourier transform infrared, proton nuclear magnetic resonance, and Carbon Hydrogen Nitrogen (CHN) analyzer. The inherent viscosities (ηinh) of the polyurethanes measured by Ubbelohde viscometer were in the range of 0.2324–0.2760 dl/g. Thermal behavior of the polyurethanes was investigated using differential scanning calorimetry and thermogravimetric analysis. The molecular orientation in polyurethane films was induced by a corona poling, and this was ascertained using ultraviolet-visible spectrophotometer and atomic force microscope. The thicknesses and refractive indices of thin films were determined by an Ellipsometer. Polyurethanes exhibited excellent solubility in most of the common organic solvents. The second harmonic generation (SHG) coefficients (d33) of the poled polyurethanes ranged from 63.20 and 95.32 pm/V at 532 nm. None of the polyurethanes showed SHG decay below 100°C, and retained 95% of the signal even up to 500 h. The resulting enhanced NLO efficiency and longer temporal stability make these polyurethanes as promising candidates for photonic devices.
关键词： Polyurethanes,Second harmonic generation,Chromophores,Thermal stability,Nonlinear optical materials
更新于2025-09-23 15:19:57
-
Photonic and Electronic Properties of Fluoride Materials || Frequency-Doubling Oxide Fluorides, Borate Fluorides, and?Fluorooxoborates
摘要： The frequency-doubling (FD) materials that are able to expand the frequency ranges of lasers by second harmonic generation (SHG) are the core of the solid-state lasers. FD is a nonlinear optical (NLO) process, in which two input laser beams with the same frequency interacting with an FD material “combine” together to generate a new output laser with twice the frequency and half the wavelength of the initial light beams. This phenomenon was first demonstrated by Franken et al. in 1961. They irradiated a quartz sample using a laser beam with a wavelength of 694 nm, and observed the output light at 347.2 nm. FD is only allowed with coherent light and in mediums without inversion symmetry.
关键词： Nonlinear Optical Materials,Borate Fluorides,Second Harmonic Generation,Frequency-doubling,Fluorooxoborates
更新于2025-09-23 15:19:57
-
Prediction of MCO [M = S, (Cl <sub/>2</sub> B) <sub/>3</sub> B] Systems with Giant Optical Birefringence and Nonlinearity in the Deep-Ultraviolet Region
摘要： Deep-ultraviolet (DUV) materials with giant optical birefringence and nonlinearity are scarce, and their discovery is very challenging. In this Communication, we predict that the MCO [M = S, (Cl2B)3B] compounds containing the polar C?O motif, which have been synthesized in the experiments, could be the ?rst material systems to achieve this rare capability. First-principles calculations demonstrate that (Cl2B)3BCO and SCO exhibit the largest second-harmonic-generation e?ect (～4.4 pm/V) and the largest birefringence (～0.6) in all known DUV nonlinear-optical (NLO) crystals. In addition, SCO might be a DUV NLO material for the practical 193.7 nm laser output. Our discovery could enrich the structural chemistry of NLO crystals and advance the development of functional DUV optical materials.
关键词： Deep-ultraviolet,nonlinearity,polar C?O motif,DUV nonlinear-optical crystals,first-principles calculations,MCO compounds,second-harmonic-generation,optical birefringence
更新于2025-09-23 15:19:57
-
Non-parabolic potential dependence of optical second harmonic generation from the Si(111) electrode/electrolyte interface
摘要： We performed potential dependent second harmonic generation (SHG) measurements on the Si(111) electrolyte interface at different azimuthal angles and for different polarization combinations. When the external potential was biased from the equilibrium potential to the flatband potential (Efb), the SHG intensity decreased linearly with the potential when the azimuthal angle was oriented at 301. This linearity extends well beyond the linear region of the Mott–Schottky plot as measured traditionally by capacitance measurements. When the external potential was scanned from Efb toward more negative potentials, the response of SHG intensity showed quadratic behavior and can be described by the parabolic model. The non-parabolic potential dependence cannot be explained with the parabolic model proposed from previous literature. Such asymmetric behavior only implied that the interfacial structure of the Si(111) electrode changes from semiconductor to metal with the applied electric potential biased negatively, i.e. with accumulation of electrons in the surface region. The anisotropic contribution from the Si(111) electrode can also significantly affect the SHG response as seen where the minimum of the potential dependent SHG curve shifts away from Efb.
关键词： potential dependence,Si(111) electrode,electrolyte interface,non-parabolic behavior,second harmonic generation
更新于2025-09-23 15:19:57
-
Nonlinear Optical Properties of CdS Semiconductor nanowires
摘要： In this work, we report on the nonlinear optical properties in single Cadmium sulfide nanowires (CdS NWs). The high qulity growth of CdS semiconductor nanowires were synthesized by chemical vapor deposition (CVD) method. The as-obtained products were characterized by X-ray diffraction (XRD) , Scanning electron microscopy (SEM), and the energy dispersive X-ray spectrom (EDS) was used to determine the specific elemental distribution and show purity of the CdS semiconductor nanowires . The excitation of femtosecond laser(800 nm, 50 fs, 80 MHz) was used to study the nonlinear optical properties of CdS nanowires, such as the Second Harmonic Generation(SHG) and optical waveguide effect. CdS NW has a second harmonic generation with a blue emission bands at a wavelength of 400 nm . Finally, based on the dark field image of the CCD taken and combined with the spectrum, it is proved that CdS NW has an optical waveguide effect.
关键词： Cadmium sulfide (CdS),Waveguide,nanowires (NWs),Second- Harmonic Generation (SHG),Chemical Vapor Deposition (CVD)
更新于2025-09-19 17:15:36
-
Cation-tuned synthesis of the A <sub/>2</sub> SO <sub/>4</sub> ·SbF <sub/>3</sub> (A = Na <sup>+</sup> , NH <sub/>4</sub><sup>+</sup> , K <sup>+</sup> , Rb <sup>+</sup> ) family with nonlinear optical properties
摘要： Four antimony fluoride sulfates named A2SO4·SbF3 (A = Na+, NH4+, K+, Rb+) have been successfully synthesized using a hydrothermal method by introducing Sb3+ cations with a stereochemically active lone pair in sulfates and subsequently tuning the structure through the second monovalent cations. All of the title compounds are stoichiometrically equivalent materials which share a common structural motif composed of a distorted SO4 tetrahedron and an asymmetric SbF3 polyhedron. However, the macroscopic centricities of these four compounds are significantly influenced by the size and coordination environment of cations; Na2SO4·SbF3 crystallizes in centrosymmetric space groups Cmca and (NH4)2SO4·SbF3 in Pbca, while K2SO4·SbF3 and Rb2SO4·SbF3 crystallizes in noncentrosymmetric space group P212121. Complete characterization including thermal analyses, infrared and UV-vis spectroscopy, and theoretical calculations is also reported. Powder second harmonic generation measurement for noncentrosymmetric K2SO4·SbF3 and Rb2SO4·SbF3 indicated that both of them are type I phase-matchable.
关键词： hydrothermal synthesis,cation tuning,nonlinear optical materials,antimony fluoride sulfates,second harmonic generation
更新于2025-09-19 17:15:36
-
Second-order nonlinear optical properties of Stenhouse photoswitches: insights from density functional theory
摘要： We report the first investigation of the second-order nonlinear optical (NLO) properties of donor–acceptor Stenhouse adducts (DASAs), an emerging class of colored photochromes that undergo photoswitching with visible light to a colorless form. By using time-dependent density functional theory, we provide insights into the relationships linking the nature of the chemical substituents to the amplitude and contrasts of the NLO response. Solvent and frequency dispersion effects are also analyzed. The calculations predict that DASAs behave as high contrast NLO switches, a finding that extends their potential applications to photo-responsive NLO materials and devices.
关键词： photoswitching,Stenhouse photoswitches,nonlinear optical properties,density functional theory,second harmonic generation
更新于2025-09-19 17:15:36
-
Rb <sub/>10</sub> Zn <sub/>4</sub> Sn <sub/>4</sub> S <sub/>17</sub> : A Chalcogenide with Large Laser Damage Threshold Improved from the Mn-Based Analogue
摘要： In the military and civilian fields, with the development of new technologies, high-powered nonlinear optical (NLO) crystals demonstrate broad application prospects. For purposes of designing a better NLO material, a new chalcogenide Rb10Zn4Sn4S17 was successfully designed with a high temperature solid-state method on the basis of previously reported compound Sr3MnSn2S8. The experimental results indicate that Rb10Zn4Sn4S17 possesses a prominent band gap of 3.59 eV, compared with the laser damage threshold (LDT) of Sr3MnSn2S8 (3 times that of AgGaS2); Rb10Zn4Sn4S17 shows an outstanding LDT about 5 times that of AgGaS2. Meanwhile, it has an ideal second harmonic generation (SHG) response approximately 0.7 times that of AgGaS2.
关键词： second harmonic generation (SHG),laser damage threshold (LDT),chalcogenide,nonlinear optical (NLO) crystals
更新于2025-09-19 17:13:59