- 标题
- 摘要
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- 实验方案
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Cylindrical Vector Beam Fibre Laser Based on photonic lantern
摘要： We demonstrate a linear-cavity continuous-wave (CW) fibre laser generating cylindrical vector beams (CVBs) using a photonic lantern as transverse mode converter and mode splitter. The CVB fibre laser operates at a center wavelength of 1553.1 nm, with a 3 dB linewidth of less than 0.08 nm and a signal-to-background ratio of > 45 dB. The measured purity of the radially and azimuthally polarized beams is > 96%.
关键词： continuous-wave,Cylindrical Vector Beam,photonic lantern
更新于2025-11-28 14:24:03
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Sub-milliampere-threshold continuous wave operation of GaN-based vertical-cavity surface-emitting laser with lateral optical confinement by curved mirror
摘要： The continuous wave operation of a gallium-nitride-based vertical-cavity surface-emitting laser (GaN-based VCSEL) that uses boron ion implantation for lateral current confinement and a curved mirror for lateral optical confinement was investigated. The threshold current was 0.25 mA (Jth = 3.5 kA cm?2) for a 3 μm diameter current aperture at room temperature and the lasing wavelength was 445.3 nm. This is the lowest threshold current recorded for a GaN-based VCSEL. This result is considered to be a milestone for the further miniaturization of GaN-based VCSELs by the implementation of lateral optical confinement due to the incorporation of a curved mirror.
关键词： continuous wave operation,threshold current,lateral optical confinement,GaN-based VCSEL,curved mirror
更新于2025-11-28 14:23:57
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High-Power Continuous-Wave and Acousto-Optical Q-Switched Ho:(Sc <sub/>0.5</sub> Y <sub/>0.5</sub> ) <sub/>2</sub> SiO <sub/>5</sub> Laser Pumped by Laser Diode
摘要： We experimentally investigate the continuous-wave (cw) and acousto-optical (AO) Q-switched performance of a diode-pumped Ho:(Sc0.5Y0.5)2SiO5 (Ho:SYSO) laser. A fiber-coupled laser diode at 1.91 ??m is employed as the pump source. The cw Ho:SYSO laser produces 13.0 W output power at 2097.9 nm and 56.0% slope efficiency with respect to the absorbed pump power. In the AO Q-switched regime, at a pulse repetition frequency of 5 kHz, the Ho:SYSO laser yields 2.1 mJ pulse energy and 21 ns pulse width, resulting in a calculated peak power of 100 kW. In addition, at the maximum output level, the beam quality factor of the Q-switched Ho:SYSO laser is measured to be about 1.6.
关键词： Laser Diode Pumped,Continuous-Wave,Acousto-Optical Q-Switched,High-Power,Ho:(Sc0.5Y0.5)2SiO5 Laser
更新于2025-11-28 14:23:57
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Low temperature fabrication of high quality gate insulator in metal-oxide-semiconductor capacitor using laser annealing
摘要： This paper reports the fabrication of a high quality gate oxide for metal-oxide-semiconductor field effect transistors using a continuous wave blue laser. A thin Zr metal layer was inserted between the dielectric and substrate to increase laser absorption and reduce the interface layer. A simulation of laser irradiation showed that metal layer insertion induces a significant increase in temperature during laser annealing compared to the dielectric without a metal layer. The laser annealed capacitor with a 1 nm-thick Zr metal layer showed superior electrical characteristics, such as high capacitance, low leakage current, low fixed charge density and low interface state density. Based on these results and the economic advantage of blue laser diodes, this technique can be a solution for low temperature processes, such as monolithic 3-dimensional integration, where low temperature processes are required.
关键词： 445 nm wavelength,Zirconium oxide,scavenging effect,laser anneal,blue,MOSCAP,continuous wave,visible laser
更新于2025-11-14 17:28:48
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[IEEE 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Tainan, Taiwan (2018.11.5-2018.11.7)] 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - A CMOS 76-81 GHz 2TX 3RX FMCW Radar Transceiver Based on Mixed-Mode PLL Chirp Generator
摘要： A fully integrated 76-81 GHz frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) in 65nm CMOS is presented. Two transmitters (TXs) and three receivers (RXs) are integrated for MIMO processing. A 38.5 GHz mixed-mode PLL with reconfigurable loop bandwidth and frequency doubling scheme are employed to generate the reconfigurable FMCW chirp waveforms. Passive voltage-mode down-conversion is utilized to improve the RX linearity against TX leakage. A bottom-switching PA is proposed to realize the Bi-Phase modulation, and the magnetically-coupled resonator technique is used to effectively expand the link bandwidth. Measurement results show that the FMCW TRX could generate reconfigurable chirps with the bandwidth from 250 MHz to 4 GHz and the period from 600 us to 10 ms. The root-mean-square (RMS) frequency error is less than 251 kHz. The TX maximum output power is 13.4 dBm and is adjustable within 3 dB by reconfiguring its LDO output voltage. The RX achieves 15.3 dB noise figure and -8.5 dBm RF input-referred PldB. Real-time experiments are carried out using the proposed TRX chip, in which the measured average distance error is 10 cm. The overall power consumption is 921mW with 2-TXs and 3-RXs powered on.
关键词： transceiver,PLL,CMOS,mm-wave,Radar,frequency-modulated continuous-wave (FMCW)
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - First GMTI Results of the MIRANDA-35 Sensor
摘要： Frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) are nowadays frequently exploited for producing electro-magnetic images of the earth surface. In this paper, we present first ground moving target indication (GMTI) results of the 2016 campaign with the FMCW airborne system MIRANDA-35, and quantify the overall performances. More precisely, two specific operating modes, namely the along-track interferometry (ATI) and exo-clutter processing (EXO), are discussed in more detail. The system proved to be capable of providing GMTI products with reliable detection rates and acceptable false alarm rates.
关键词： FMCW,GMTI,SAR,Ground Moving Target Indication,Synthetic Aperture Radar,Exo-Clutter,Frequency-Modulated Continuous-Wave,Interferometry
更新于2025-09-23 15:23:52
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Boundary Data Analysis of Continuous Wave Domain Diffuse Optical Tomography with Structured Refined Mesh Algorithm for Product Quality Control
摘要： Diffuse optical tomography is promising technology for non destructive evaluation on product quality control. In order to improve the forward sensitivity, structured refine mesh method was applied on continuous wave domain diffuse optical tomography imaging. This study was conducted on numerical and phantom object. These objects were illuminated by the near infrared source from object’s boundary. To obtain the boundary parameter data, a set of near infrared detector were placed on the periphery of the object. To validate our proposed forward analysis method, boundary parameter data of simulation are shown in comparison with that of experiment. In this study, we vary the position and the value of optical coefficient of defect on the object then we analyze the forward problem sensitivity. The result of this study indicated that continuous wave domain-diffuse optical tomography is promising for product quality control.
关键词： Forward analysis,structured refine mesh,continuous wave domain,optical tomography
更新于2025-09-23 15:23:52
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Leakage Mitigation in Heterodyne FMCW Radar for Small Drone Detection With Stationary Point Concentration Technique
摘要： To prevent potential hazards posed by fast-evolving drones, it is of importance to develop a radar system for drone detection. Frequency modulated continuous wave (FMCW) radars are widely used for that purpose. Heterodyne architectures are preferred for them to mitigate dc offset errors. Having said that, FMCW radars suffer from permanent leakage from the transmitter into the receiver. The leakage phase noise raises the total noise floor and limits the radar sensitivity. Here, we propose a stationary point concentration (SPC) technique in order to overcome the challenges. The SPC technique concentrates the leakage phase noise on a stationary point to alleviate the impact of the noise. The technique can be realized using digital signal processing without additional hardware. The results show that the proposed technique significantly lowers the noise floor.
关键词： heterodyne,down-conversion,leakage,digital signal processing (DSP),frequency modulated continuous wave (FMCW) radar,stationary point concentration (SPC) technique,stationary point,phase noise,noise floor
更新于2025-09-23 15:22:29
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Influence of gold nanolayer coating on the continuous-wave laser ablation of a pure aluminum surface: Evaluations of structural and optical features
摘要： In this paper, formation of uniform and large-area micro/nanostructures on pure aluminum surfaces using a continuous-wave laser irradiation is presented. Gold nanolayer coating was utilized as a confinement layer for controlling the possible hydrodynamic phenomena in a molten area. Dependency of the laser-induced morphology on the thickness of a gold coating was investigated in this regard. Scanning electron microscopy, energy dispersive spectroscopy, grazing test of the X-ray diffraction, and optical absorption/reflection spectroscopy in UV/visible/IR ranges were employed to characterize the samples. Results showed that the formation of uniform structures of average sizes of 50 nm-5μm on aluminum surface was possible following the irradiation of a continuous-wave CO2 laser, delivering 130 W beam power. Alterations of the surface morphology brought about an increase in specific absorption peaks at the UV region and the appearance of an absorption peak in the visible range. In addition, these structure-covered surfaces provided interesting reflection behaviors in different spectral areas, which can clearly reflect their high potential to be used as selective solar absorbers. The results of this investigation indicated that optical characteristics such as absorption and emission coefficients as well as ξ factor were 0.98, 0.13, and 7.53, respectively. It can therefore be concluded that this process can be considered an efficient and fast technique to fabricate selective solar absorbers.
关键词： Nanostructures,Aluminum,Selective solar absorber,Sputtering,Nanolayer,Continuous-wave CO2 laser,Gold,Black carbon
更新于2025-09-23 15:22:29
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Design of Collectors for High Average/Continuous-Wave Power Gyro-Devices
摘要： In this paper, techniques to improve the collector’s dissipated power density threshold are discussed first. Then, theories of electron collection are presented, aiming at improving the effective electron-collecting area and collecting uniformity. Specifically, the layered electron beam collection in linear-taper collector, respectively, with constant and gradually varying magnetic field is modeled and discussed. Results indicate that a quasi-rectangular shape collection can be realized as the tangential collection dominates. Finally, the using of a compensation coil is analyzed and the corresponding collector is designed.
关键词： gyro-devices,high average/continuous-wave power,dissipated power (DP) density,Collectors
更新于2025-09-23 15:22:29