- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Hong Kong, China (2018.11.5-2018.11.9)] 2018 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Modeling Modal Properties of Antiresonant VCSEL with Bessel Expansion Transfer Method
摘要： We study optical properties of an ARROW-VCSEL, in which the anti-resonant effect is provided by an oxide island manufactured with planar oxidation inside the optical cavity. We implement a novel Bessel Expansion Transfer Method to show how this effect alters the nature of the laser modes by forcing qualitative change in the optical field profiles.
关键词： single-mode,resonance,ARROW-VCSEL,Bessel expansion,modal transfer method,orthogonality,oxidation
更新于2025-09-23 15:22:29
-
[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 - A Ground Slow Moving Target Detection Method for High-Speed Maneuvering SAR Via Bidirectional Imaging Mode
摘要： High-speed maneuvering synthetic aperture radar (SAR) moves with a high speed and complex trajectory. It's difficult for it to detect the ground slow moving target using the conventional detection method. To solve this problem, a slow moving target detection method via bidirectional imaging mode (BiDi) is proposed in this paper. The influence of the motion parameters on the moving target's imaging position is discussed, and the location relationship of the moving target between the two SAR images acquired via BiDi mode is also analyzed. The along track separation in BiDi mode can make an azimuth offset of the moving target between the two SAR images. On the other hand, the moving target's opposite imaging position offset in azimuth direction will further increase this azimuth offset. While there is no offset in the range direction of the moving target due to it's azimuth velocity. According to the position differences of the moving target in the two SAR images, the ground slow moving target can be detected successfully. Simulation results have verified the effectiveness of the proposed method.
关键词： slow moving target,BiDi mode,detection,High-speed maneuvering SAR
更新于2025-09-23 15:22:29
-
Anapole Modes in Hollow Nanocuboid Dielectric Metasurfaces for Refractometric Sensing
摘要： This work proposes the use of the refractive index sensitivity of non-radiating anapole modes of high-refractive-index nanoparticles arranged in planar metasurfaces as a novel sensing principle. The spectral position of anapole modes excited in hollow silicon nanocuboids is first investigated as a function of the nanocuboid geometry. Then, nanostructured metasurfaces of periodic arrays of nanocuboids on a glass substrate are designed. The metasurface parameters are properly selected such that a resonance with ultrahigh Q-factor, above one million, is excited at the target infrared wavelength of 1.55 μm. The anapole-induced resonant wavelength depends on the refractive index of the analyte superstratum, exhibiting a sensitivity of up to 180 nm/RIU. Such values, combined with the ultrahigh Q-factor, allow for refractometric sensing with very low detection limits in a broad range of refractive indices. Besides the sensing applications, the proposed device can also open new venues in other research fields, such as non-linear optics, optical switches, and optical communications.
关键词： metasurfaces,dielectric nanoparticles,anapole mode,sensing devices
更新于2025-09-23 15:22:29
-
An optimized harmonic probe with tailored resonant mode for multifrequency atomic force microscopy
摘要： For simultaneously measuring specimen’s surface morphology and material properties, multifrequency atomic force microscopy is often employed. In this kind of atomic force microscopy, if the probe’s higher-order resonance frequencies match the integer multiples of its fundamental frequency, the probe’s responses at such harmonic frequencies will be enhanced. Meanwhile, an enlarged effective slope during vibration at the probe’s tip results in an improved probe sensitivity. Moreover, increasing the probe’s natural frequency leads to a fast scanning speed. In this study, we propose to design cantilever probes that satisfy the aforementioned requirements via a structural optimization technique. A cantilever probe is represented by a three-layer symmetrical geometric model, and its width profile is continuously varied through the optimization procedure. Thereafter, an optimized design of probe considering the fifth harmonic is prepared by focused ion beam milling. Both simulation and experiment results show that the prepared probe agrees well with design requirements.
关键词： resonant frequency,tapping-mode,structural optimization,modal assurance criterion,Multifrequency atomic force microscopy
更新于2025-09-23 15:22:29
-
Nonlinear multimodal interference for ytterbium-doped all-fiber mode-locking noise-like pulse generation
摘要： This work demonstrates the generation of the noise-like pulse (NLP) in an all-normal-dispersion passively mode-locked ytterbium-doped ring laser cavity with nonlinear multimodal interference as an equivalent all-fiber saturable absorber, for the first time to the best of our knowledge. Depending on the appropriate optimization of the intra-cavity birefringence and reasonable control of the curving curvature of the multimode fiber, self-started NLP operation can be built and maintained within a wide pump range. Additionally, the effect of the multimode fiber length on the NLP mode-locking performance and the generation of the high power NLP have also been experimentally studied.
关键词： ytterbium-doped fiber,all-fiber laser,nonlinear multimodal interference,noise-like pulse,mode-locking
更新于2025-09-23 15:22:29
-
Dependence on hydrostatic pressure in two-dimensional triangular photonic crystals
摘要： The plane wave expansion method is used to calculate photonic band structures for transverse electric (TE) polarization, in a two-dimensional (2D) photonic crystal with a hexagonal lattice composed air holes with triangular cross sections embedded in a semiconductor (GaAs) background. This study focuses on the dependence of the GaAs dielectric constant on pressure and temperature. The air holes are isosceles triangles with fixed areas. We found that the width of the photonic band gap increases, when the internal angle of the triangle and the angle of rotation in the unit cell are increased at constant hydrostatic pressure values. The width of the photonic band gap remains unchanged when the hydrostatic pressure is increased at fixed internal and rotation angle values. In addition, when considering an H1 defect in the crystal, using the supercell technique, we find that the number of defective modes within the photonic band gap increases with the triangle rotation in the unit cell.
关键词： plane wave expansion method,hydrostatic pressure,defect mode,Photonic crystal,semiconductor
更新于2025-09-23 15:22:29
-
[IEEE 2018 5th International Conference on Information Science and Control Engineering (ICISCE) - Zhengzhou, China (2018.7.20-2018.7.22)] 2018 5th International Conference on Information Science and Control Engineering (ICISCE) - Improve Power Flow Control and Performance Analysis of MVDC Grid Connected PV System
摘要： In this study a control strategy of two-level Three-phase grid connected PV system by using SVPWM method is proposed for distribution and generation system. Traditional grid rectifier brings a lots of harmonics pollution, to decrease these harmonics, in this control system technique a double closed loop control based on. (ISMC). Integral. Sliding. Mode. Control.internal current loop and voltage control external loop is presented. The main objective of this controller is, low error (SS) steady state, enhanced voltage regulation, unity power factor, little (THD) total harmonic pollution distortion and into consideration. By using small disturbance Matlab/Simulink software simulation results shows the proposed control system is effective, good dynamics and fast response which open new insights in distribution systems taken
关键词： Three-phase PV inverter,SVPWM,sliding mode,double closed loop
更新于2025-09-23 15:22:29
-
Low-cost, Inkjet-printed UHF RFID Tag based System for Internet of Things Applications using Characteristic Modes
摘要： The radio frequency identification (RFID) has emerged Internet of things (IoT) into the identification of things. This paper presents, a low-cost smart refrigerator system for future internet of things applications. The proposed smart refrigerator is used for automatic billing and restoring of beverage metallic cans. The metallic cans can be restored by generating a product shortage alert message to a nearby retailer. To design a low-cost and low-profile tag antenna for metallic items is very challenging, especially when mass production is required for item-level tagging. Therefore, a novel ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna is designed for metallic cans by exploiting the metallic structure as the main radiator. Applying Characteristics mode analysis (CMA), we observed that some characteristic modes associated with the metallic structure could be exploited to radiate more effectively by placing a suitable inductive load. Moreover, a low cost, printed (using conductive ink) small loop integrated with meandered dipole used as an inductive load, which was also connected with RFID chip. The 3-dB bandwidth of the proposed tag covers the whole UHF band ranging from 860 - 960 MHz when embedded with metal cans. The measured read range of the RFID tag is more than 2.5 meters in all directions to check the robustness of the proposed solution. To prove the concept, a case study was performed by placing the tagged metallic cans inside a refrigerator for automatic billing, 97.5 % tags are read and billed successfully. This study paves the way for tagging metallic bodies for tracking applications in domains ranging from consumer devices to infotainment solutions, which enlightens a vital aspect for the Internet of Things (IoT).
关键词： Characteristic mode theory (CMT),smart refrigerator,radio frequency identification (RFID) tag antenna,Internet of Things (IoT)
更新于2025-09-23 15:22:29
-
Gain and bandwidth of the TM-mode gyrotron amplifiers
摘要： This work discusses the feasibility of gyrotron amplifiers using TM modes by investigating their dispersion relations starting with the relativistic Vlasov equation. For an input signal carrying a real frequency x, the complex wave number kz solved from the dispersion relation tells us the growth rate and the bandwidth of an amplifier. Three modes (TE01, TM11, and TM01) operating at the fundamental cyclotron harmonic (s ? 1) with the same cutoff frequency will be discussed. The results show that the TM11- and TM01-mode gyrotrons require much higher beam current than the TE01-mode gyrotron traveling-wave tube (gyro-TWT) amplifier. The TM modes are unsuitable for the gyro-TWT amplifier as discovered by other authors. The gyrotron backward-wave (gyro-BW) amplifier is also examined. The dispersion relations indicate that the TM modes are as good as the TE modes. The gain and bandwidth of the TM11-mode gyrotron backward-wave amplifier (gyro-BWA) are studied by changing either the magnet field or the beam voltage. The TM11 mode is suitable and has a decent bandwidth for the operation of the gyro-BW amplifier.
关键词： relativistic Vlasov equation,TE01 mode,TM modes,gyro-BW amplifier,TM11 mode,gyrotron amplifiers,gyro-TWT amplifier,TM01 mode,dispersion relations
更新于2025-09-23 15:21:21
-
[Springer Series in Optical Sciences] Fano Resonances in Optics and Microwaves Volume 219 (Physics and Applications) || Dark-Mode Characteristics of Metasurfaces Engineered by Symmetry Matching of Resonant Elements and Electromagnetic Fields
摘要： We revisit the engineering of metasurfaces displaying sharp spectral features and conventionally relying on electromagnetically induced transparency resulting from Fano-type interference between dark and bright resonant elements. The aim of the developed approach based on symmetry considerations is to show that electromagnetically induced transparency and dark mode excitation are not necessarily associated. We bring theoretical and experimental evidence in the microwave domain that electromagnetically induced transparency and dark mode excitation can be achieved in an independent manner by using distinctly different mechanisms. The use of these distinctly different mechanisms provides higher flexibility for metasurfaces engineering and results in a great improvement of their spectral performances.
关键词： metasurfaces,dark mode,symmetry matching,bright mode,electromagnetically induced transparency,Fano-type interference
更新于2025-09-23 15:21:21