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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • Distributed optical fiber sensing
  • Optical frequency domain reflection
  • Polynomial regression algorithm
  • Nonlinear tuning compensation
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Hebei University of Technology
777 条数据
?? 中文（中国） ▾

  • Effect of different hardness and melting point of the metallic surfaces on structural and optical properties of synthesized nanoparticles

    摘要： The relations between macroscopic and microscopic characteristics of materials are of utmost importance for synthesis of multi-atomic structures with advanced properties. We analyze the influence of pulse duration, pulse energy and temperature of liquid on the process of formation of nanoparticles (NPs) of the metals (In, Sn, Zn and W) with different hardness and melting temperature by laser ablation in liquid environment. Composition, morphology dynamics and properties of nanoparticle suspensions are studied using TEM analysis and Z-scan technique. The nonlinear optical properties of NPs are analyzed at 800 and 400 nm using 60 fs and 200 ps pulses. We show that the temperature of liquid environment influences the formation of NPs and their nonlinear optical properties. In addition, pulse energy have little influence on the formation, morphology and size of NPs during ablation of low hardness and melting point metal (In). However, pulse duration plays a very important role during the formation of NPs, especially the ultra-short pulse has a positive effect on the preparation of NPs with smaller particle size.

    关键词： nonlinear optical properties,metal nanoparticles,laser ablation in liquid

    更新于2025-09-23 15:23:52

  • Growth, optical, mechanical and thermal behavior of unidirectionally grown L-Glutaminium p-Toluenesulfonate crystal

    摘要： Organic crystal of L-Glutaminium p-Toluenesulfonate (LGPT) was grown unidirectional by Sankaranarayanan and Ramasamy (SR) method. The grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group P21. High resolution XRD confirms crystalline perfection of the grown crystal. Optical transmission shows that unidirectional grown crystal has higher transmittance and the lower cut-off wavelength is 290 nm. The emission wavelength of grown crystal is 410 nm and emission region is confirmed by luminescence spectra. The laser damage threshold value of unidirectional crystal has increased by 0.3 GW/cm2. The grown LGPT crystals belong to hard material category and it confirms the normal indentation size effect. The grown LGPT crystal is thermally stable upto 165 oC and decomposition of the molecules were elucidated by using TGA and DSC. Powder second harmonic generation measurement confirms the efficiency of the grown LGPT crystal is 0.8 times that of KDP.

    关键词： Nonlinear optical materials,Crystal growth,Recrystallization,Optical properties

    更新于2025-09-23 15:23:52

  • Diagrammatic approach to nonlinear optical response with application to Weyl semimetals

    摘要： Nonlinear optical responses are a crucial probe of physical systems including periodic solids. In the absence of electron-electron interactions, they are calculable with standard perturbation theory starting from the band structure of Bloch electrons, but the resulting formulas are often large and unwieldy, involving many energy denominators from intermediate states. This work gives a Feynman diagram approach to calculating nonlinear responses. This diagrammatic method is a systematic way to perform perturbation theory, which often offers shorter derivations and also provides a natural interpretation of nonlinear responses in terms of physical processes. Applying this method to second-order responses concisely reproduces formulas for the second-order-harmonic shift current. We then apply this method to third-order responses and derive formulas for third-order-harmonic generation and self-focusing of light, which can be directly applied to tight-binding models. Third-order responses in the semiclassical regime include a Berry curvature quadrupole term, whose importance is discussed including symmetry considerations and when the Berry curvature quadrupole becomes the leading contribution. The method is applied to compute third-order optical responses for a model Weyl semimetal, where we find a new topological contribution that diverges in a clean material, as well as resonances with a peculiar linear character.

    关键词： Weyl semimetals,perturbation theory,Berry curvature,nonlinear optical responses,Feynman diagrams

    更新于2025-09-23 15:23:52

  • Influence of experimental parameters on linear, nonlinear optical and ultrafast dynamics properties of In doped ZnO nanorods

    摘要： In-doped ZnO (IZO) nanorods have been successfully synthesized by chemical vapour deposition method. The structure, morphology and linear optical properties of IZO nanorods have been characterized. The excitation intensity and temperature - dependent the photoluminescence of IZO nanorods were analyzed. The nonlinear optical absorption properties were studied by using the Z-scan technique with same wavelengths at different laser pulses and energies. IZO nanorods showed two-photon absorption (TPA) mechanism at 532 nm. In the low-energy pulse regime, IZO nanorods showed TPA induced ground state saturable absorption (SA). However, with increasing the energy pulse regime, an apparent TPA induced reverse-saturable absorption (RSA) was observed. The ultrafast dynamics properties of IZO nanorods were investigated by the pump-probe technique under different laser parameters. The femtosecond transient absorption spectra show that the few decades picosecond component has been assigned to the shallow donor mixed with donor bound recombination, and the slowed components represent the decay from donor–acceptor pair recombination.

    关键词： Zinc oxide,Nonlinear optics properties,Photoluminescence,Chemical vapour deposition

    更新于2025-09-23 15:23:52

  • Nonlinear Diffraction in Asymmetric Dielectric Metasurfaces

    摘要： Metasurfaces provide new and promising mechanisms to control and manipulate light at the nanoscale. While most metasurfaces are designed to operate in the linear regime, it was recently shown that such metasurfaces may also generate nonlinear signal, by manipulating the higher order susceptibility terms. As such, metasurfaces can generate additional harmonics, without the need for light propagation, as typically occur in nonlinear crystals. While such demonstrations typically rely on the nonlinear properties of metals, we hereby report the design, fabrication and experimental characterization of a resonant dielectric metasurface made of amorphous silicon to create and manipulate second harmonic light and control its diffraction patterns. As shown in the paper, the second harmonic generation of light follows selection rules which rely on the asymmetry of the meta-atom. Given the fact that silicon crystals are centrosymmetric, the generation of second harmonic signal in amorphous silicon is intriguing. In fact, second harmonic signal is generated mostly from the surface of the meta atom. It is the use of nanostructures that increases the surface to volume ratio and enables second harmonic generation. Additionally, the meta atom is designed to exploit its spectral resonances in the principal and the second harmonic frequencies for providing electromagnetic field enhancement which assist in boosting up the generation of second harmonic signal.

    关键词： Metasurfaces,Nonlinear optics,Dielectric metasurfaces,Phase gradient metasurfaces

    更新于2025-09-23 15:23:52

  • Low threshold, dual-wavelength, mid-infrared optical parametric oscillator

    摘要： In this letter, we demonstrated a dual-wavelength (DW) mid-infrared optical parametric oscillator (OPO) that was pumped by two independent fiber lasers fixed at 1018 nm and 1080 nm, and realized phase-matched signal beam coupling by tuning grating period of PPLN. Based on signal beam coupling, two interesting phenomena were observed for the first time. One is that the OPO threshold for 1018 nm and 1080 nm pump beams could be drastically lowered from 15.4 W to 266 mW and from 13.5 W to 1.38 W separately. The other is that the total idler power obtained when the OPO was simultaneously pumped by two fiber lasers was higher than sum of idler power obtained when the OPO was independently pumped by two fiber lasers, revealing obvious parametric gain enhancement. It also indicated that the two independent OPO processes became coherent when two signal beams were coupled. The results exhibit great potential in practical applications such as frequency down-conversion of some special near-infrared laser sources such as pulsed single-frequency sources, spectrum high-speed swept sources, and ultra-short pulse sources with low duty cycle.

    关键词： fiber lasers,Infrared lasers,nonlinear,nonlinear crystals

    更新于2025-09-23 15:22:29

  • Solitons solutions of nonlinear Schr?dinger equation in the left-handed metamaterials by three different technique

    摘要： This paper, derives the exact traveling-wave solution and soliton solutions of nonlinear Schr?dinger equation (NLSE) with higher-order nonlinear terms of Left-handed metamaterials (LHMs), the authors apply three different methods, namely: csch function method, the exp(?φ(ξ))-Expansion method and the simplest equation method. The results obtained are Dark, Bright solitons and other solutions, which are well known in optics metamaterials and LHMs.

    关键词： Exact Soliton solutions and other solutions of nonlinear Schr?dinger equation with higher-order nonlinear terms,the exp(?φ(ξ))-Expansion method method,csch function method,the simplest equation

    更新于2025-09-23 15:22:29

  • Adaptive Nonlinear Equalization of a Tunable Bandpass Filter

    摘要： The mitigation of third-order intermodulation distortion produced by a nonlinear tunable bandpass filter (BPF) in a digital receiver channel is demonstrated. An iterative solution is proposed, in the use of the least-mean-square algorithm, as an effective way to allow the correction coefficients to adapt to the changes in the system characteristics when the center frequency is changed. Results are shown using a two-pole, varactor-loaded BPF, and an Analog Devices AD9371 transceiver.

    关键词： Adaptive signal processing,nonlinear distortion and intermodulation distortion (IMD),nonlinear filters,least mean square

    更新于2025-09-23 15:22:29

  • [IEEE 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Cartagena des Indias (2018.9.10-2018.9.14)] 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Exact Solution for the Electromagnetic Field Excited by a Pulsed Filamentary Electric Current in a Nonlinear Nondispersive Medium

    摘要： Radiation from a pulsed ?lamentary electric current immersed in a nonlinear nondispersive medium is studied. Two cases where such a medium is homogeneous or has a power-law permittivity pro?le in the linear limit are considered and the spatial distributions of the source-excited ?elds in the nonlinear regime are analyzed in these cases. Concerning the propagation of pulsed signals excited by the source, the emphasis is placed on the formation of cylindrical electromagnetic shock waves and the behavior of the propagation velocities of wave pro?les in the nonlinear medium. Special attention is also paid to the in?uence of the pulse shape on the manifestation of the studied nonlinear phenomena.

    关键词： pulsed electric current,nonlinear nondispersive medium,electromagnetic shock waves

    更新于2025-09-23 15:22:29

  • Nonlinear transmittance of a diffusion-doped single crystal ZnSe:Fe <sup>2+</sup> at a wavelength of 2940?nm at low and room temperature

    摘要： The nonlinear transmittance of a single crystal ZnSe:Fe2+ sample was measured at low and room temperature during the action of a laser pulse with a wavelength of 2940 nm. It was found that in a strong field (fluence 1.3 J cm?2, a laser pulse duration of 320 ns, a peak intensity of 4.1 MW cm?2), the sample transmittance is about 70% at room and 77% at low temperature. In a single crystal ZnSe:Fe2+ sample at a fluence of 1.3 J cm?2 and a spot diameter of high-power radiation of about 0.54 mm, at the temperature ?168 °C lasing was observed along the surface of the sample, when feedback was provided by scattering from the matted surface of the sample. This effect should be taken into account when nonlinear transmittance measurements are fulfilled of a diffusion doped a single crystal ZnSe:Fe2+.

    关键词： nonlinear transmittance,ZnSe:Fe2+,low temperature

    更新于2025-09-23 15:22:29