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المؤلفون: Chenyu Yao, Yingying Wang, Wei Ren, Wei Jin, Shoufei Gao
المصدر: Sensors and Actuators B: Chemical. 346:130528
مصطلحات موضوعية: Heterodyne, Materials science, Photothermal spectroscopy, business.industry, Amplifier, Metals and Alloys, Physics::Optics, Laser pumping, Photothermal therapy, Condensed Matter Physics, Laser, Signal, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, Interferometry, law, Materials Chemistry, Optoelectronics, Electrical and Electronic Engineering, business, Instrumentation
الوصف: Photothermal spectroscopy with the optical pump-probe configuration has been used for sensitive gas detection in hollow-core fibers. In this study, we demonstrate a new method of heterodyne interferometric photothermal gas sensing with a simplified sensor design and enhanced sensor stability. As a proof-of-principle, we used an interband cascade pump laser at 3.6 μm for nitrous oxide (N2O) detection in a hollow-core anti-resonant fiber (HC-ARF). A Mach-Zehnder interferometer (MZI) with a 1.5 μm near-infrared probe laser was implemented to measure the photothermal-induced refractive index change inside the HC-ARF. The probe laser was split into two beams, one transmitted through the HC-ARF and one frequency-shifted by using an acoustic-optic modulator. Both beams were recombined to generate a beat note signal, which was then demodulated by two cascaded lock-in amplifiers to extract the photothermal signal. Based on the first harmonic detection of wavelength modulation, we achieved a normalized noise equivalent absorption (NNEA) coefficient of 7.7×10−9 cm-1WHz-1/2. Compared to conventional photothermal gas sensors with the MZI configuration, our new detection scheme eliminates the sophisticated opto-mechanical stabilization system and exhibits the intrinsic immunity to the power fluctuation of the probe laser.
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2
المؤلفون: Pei-Gang Chen, Tsz Wing Lo, Dangyuan Lei, Han Gao, Wei Jin
المصدر: Advanced Functional Materials. 31:2170217
مصطلحات موضوعية: Biomaterials, Circular dichroism, Photoluminescence, Materials science, business.industry, Electrochemistry, Optoelectronics, Selective excitation, Condensed Matter Physics, Polarization (waves), business, Plasmon, Electronic, Optical and Magnetic Materials
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3
المؤلفون: Wei Jin, Han Gao, Dangyuan Lei, Pei-Gang Chen, Tsz Wing Lo
المصدر: Advanced Functional Materials. 31:2101502
مصطلحات موضوعية: Biomaterials, Circular dichroism, Photoluminescence, Materials science, business.industry, Electrochemistry, Optoelectronics, Selective excitation, Condensed Matter Physics, Polarization (waves), business, Plasmon, Electronic, Optical and Magnetic Materials
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المؤلفون: Wei Ren, Chenyu Yao, Yingying Wang, Ruifeng Kan, Pu Wang, Wei Jin, Shoufei Gao, Limin Xiao
المصدر: Sensors and Actuators B: Chemical. 303:127238
مصطلحات موضوعية: Detection limit, Distributed feedback laser, Materials science, Absorption spectroscopy, business.industry, Far-infrared laser, Metals and Alloys, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Noise (electronics), 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Path length, Materials Chemistry, Optoelectronics, Fiber, Electrical and Electronic Engineering, 0210 nano-technology, business, Absorption (electromagnetic radiation), Instrumentation
الوصف: We demonstrated the sensitive CO detection in a novel hollow-core negative curvature fiber (HC-NCF) with infrared laser absorption at 2.3 μm. The HC-NCF consists of a single ring of eight nontouching silica capillaries around the air core, providing a single-mode light delivery of the 2.3-μm distributed feedback laser. A high coupling efficiency of 90% was achieved with the aid of optimal free-space coupling optics. The hollow-core fiber was used as a gas cell for gas absorption measurement of a total path length of 85 cm. Both direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS) were adopted to demonstrate the sensor performance by detecting the CO line R(10) at 4297.7 cm−1. In scanned-wavelength DAS, we obtained a minimum detection limit (MDL) of 13 ppm CO, which was limited mainly by the existing mode noise in the HC-NCF. By applying a pressure difference of 0.8 bar between the two ends of the fiber, we demonstrated a very short gas loading time of only 5 s. Finally, we achieved a MDL of 0.4 ppm CO using the WMS technique, corresponding to a noise equivalent absorption of 1.6 × 10-7 cm−1.
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المؤلفون: Wei Jin, Hui Huang, Bin Kang, Wenlong Yin, Tao Xu, Shengquan Yu, Mingjin Tang
المصدر: Materials Letters. 173:47-49
مصطلحات موضوعية: 010302 applied physics, Materials science, Transparent ceramics, Microwave dielectric properties, business.industry, Mechanical Engineering, 02 engineering and technology, Dielectric, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, 01 natural sciences, Mechanics of Materials, Phase (matter), visual_art, 0103 physical sciences, visual_art.visual_art_medium, Optoelectronics, Relative density, General Materials Science, Ceramic, 0210 nano-technology, business, Microwave
الوصف: The microwave dielectric properties of YAG transparent ceramics were investigated. The samples were prepared by the conventional solid-state reaction technique with the high purity raw materials. And they were sintered at 1600–1800 °C for 4–12 h in the vacuum atmosphere ≤1 × 10−3 Pa. YAG transparent ceramics sintered at 1750 °C for 8 h had the pure cubic YAG phase and pore-free microstructure with relative density 99.8%, and they were highly transparent. YAG transparent ceramics had the outstanding microwave dielectric properties: er=10.8, Q×f=213,400 GHz and τf=−30 ppm/°C. The high Q×f value and low er suggested that YAG transparent ceramics would be kind of promising microwave dielectric substrate materials.
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6
المؤلفون: Ao-bo Fu, Lei Qin, Hai-feng Xu, Shao-wei Jin
المصدر: Superlattices and Microstructures. 58:53-59
مصطلحات موضوعية: Materials science, Field (physics), business.industry, Property (programming), Optical communication, Condensed Matter Physics, Optics, Optoelectronics, Weak field, General Materials Science, Relative phase, Electrical and Electronic Engineering, business, Absorption (electromagnetic radiation), Refractive index, Quantum well
الوصف: We investigated the absorptive–dispersive property of a weak field in a four-level inverted-Y quantum well system. We find that the cycling field and relative phase of the applied fields can affect the absorptive–dispersive property of a weak field dramatically, which can be used to manipulate efficiently the ultrahigh index of refraction without absorption. Our study is much more practical than its atomic counterpart due to its flexible design and controllable quantum-interference effect. Thus, it may provide some new possibilities for technological applications in optoelectronics and solid-state optical communication
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7
المؤلفون: D.N. Wang, Yiping Wang, Wei Jin, Xiaohui Fang
المصدر: IEEE Journal of Quantum Electronics. 42:866-870
مصطلحات موضوعية: Femtosecond pulse shaping, Materials science, Optical fiber, Laser diode, business.industry, Physics::Optics, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, law.invention, Gain-switching, Semiconductor laser theory, Optics, law, Fiber laser, Optoelectronics, Electrical and Electronic Engineering, business, Fabry–Pérot interferometer, Bandwidth-limited pulse
الوصف: A simple continuously wavelength-tunable fiber ring laser pulse source is demonstrated. Such a source employs a gain-switched multiple quantum-well Fabry-Perot laser diode in a self-seeding scheme and the output pulse wavelength can be tuned continuously via a tunable optical filter. The optical pulses generated exhibit a pulsewidth of 92 ps at the frequency of 2.6 GHz. Within a wide wavelength tuning range of 46 nm, the side-mode suppression ratio and the average power of the output optical pulses obtained are higher than 50.1 dB and 3.3 dBm, respectively, and the pulse spectral stability can be maintained in the whole wavelength tuning range
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::5c0a9e6e10a8f2bb6416b09d7adec2bb
https://doi.org/10.1109/jqe.2006.879815
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8
المؤلفون: D. N. Wang, Wei Jin, F. W. Tong, Hong Li
المصدر: Microwave and Optical Technology Letters. 32:458-461
مصطلحات موضوعية: Materials science, business.industry, Physics::Optics, Polarization-maintaining optical fiber, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Optics, Zero-dispersion wavelength, Fiber Bragg grating, Fiber laser, Wavelength-division multiplexing, Optoelectronics, Dispersion-shifted fiber, Electrical and Electronic Engineering, business, Lasing threshold, Photonic-crystal fiber
الوصف: A multiwavelength erbium-doped fiber ring laser is proposed, which is based on two Mach–Zehnder interferometers in a cascade configuration. One of the interferometers acts as a wavelength filter, and the other, exhibiting a relatively small optical path difference, determines the number of lasing wavelengths. By the use of an optical switch, the operating wavelengths can be shifted between two wavelength bands, centered at 1555 and 1565 nm. A stable simultaneous ten-wavelength lasing operation with amplitude fluctuations 25 dB over the whole operating wavelength region has been obtained. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 458–461, 2002.
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المؤلفون: Li Cui, Wei Jin, Rongben Zhang, Yubiao Liu, Chuan-feng Zhu, Chen Wang, Ping Xie
المصدر: Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals. 333:135-144
مصطلحات موضوعية: Liquid-crystal display, Azo compound, Chemistry, business.industry, Stereochemistry, Annealing (metallurgy), Condensed Matter Physics, Rubbing, law.invention, chemistry.chemical_compound, Azobenzene, law, Liquid crystal, Side chain, Optoelectronics, Irradiation, business
الوصف: A novel two-step method combining rubbing and UV-irradiation based on ladderlike polysilsesquioxanes (LPS) containing cinnamate and azobenzene side chains was developed to obtain alignment layers which features a high surface pretilt angle and good stability. At the first step, a low pretilt angle of 1–3° was generated by rubbing and at the second step, an increased pretilt angle of about 11° was obtained through further UV-irradiation. The polarized optical micrograph and the conoscopic picture prove that good LC alignment state with a stable high pretilt angle can be obtained by in situ photo-crosslinking of the cinnamate side-chains through proper UV-irradiation. The high pretilt angle arises from the photo-induced tautomerization of azobenzene side chains and that is confirmed by AFM study. In particular, the annealing test near the clearing point indicates the high stability of the high pretilt state, which heralds their potential application in LCD such as producing a patterned alignment la...
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10
المؤلفون: Hoi Lut Ho, Wei Jin, Jian Ju, Y.L. Hoo
المصدر: Microwave and Optical Technology Letters. 40:378-380
مصطلحات موضوعية: Materials science, business.industry, Single-mode optical fiber, Electrical engineering, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Optoelectronics, splice, Fiber, Electrical and Electronic Engineering, business, Microwave, Photonic-crystal fiber
الوصف: The connection loss between single-mode fiber and photonic crystal fiber (PCF) is analyzed by using a full-vector finite-element method. PCF parameters for achieving low loss connection (for example, less than 0.5 dB) are reported. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 378–380, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11387
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