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Performance study of surface plasmon resonance and lossy mode resonance based fiber optic sensors utilizing silver and indium oxide layers: An experimental investigation
摘要： This study presents here the experimental investigations on a surface plasmon resonance (SPR)/lossy mode resonance (LMR) based fiber optic sensors coated with silver and indium oxide layers. Different sensing probes have been fabricated by coating (i) a single layer of indium oxide, (ii) a single layer of silver and (iii) a double layer of indium oxide and silver (with different thicknesses) symmetrically onto to the bare core of silica fiber. The sensitivity of these fiber optic sensing probes towards surrounding region refractive index variations are determined using different concentrations of sucrose solutions. It was found that sensor probe fabricated with coating of 100 nm thickness of indium oxide was two times more sensitive than the conventionally used fiber optic sensing probe coated with only silver layer. The sensitivity of a double layer coated fiber optic sensor with various thicknesses of indium oxide and silver layers is in between the two extremes of the sensitivities. This study will find suitable applications in the field of chemical and biochemical sensing. The drawbacks of silver coatings and the advantages of LMR supporting indium oxide have also been discussed.
关键词： Surface plasmons,Sensitivity,Lossy mode resonances,Thin films,Fiber optic sensors,Detection accuracy,Indium oxide
更新于2025-09-23 15:21:21
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Impact of asymmetries on fuel performance in inertial confinement fusion
摘要： Low-mode asymmetries prevent effective compression, con?nement, and heating of the fuel in inertial con?nement fusion (ICF) implosions, and their control is essential to achieving ignition. Ion temperatures (Tion) in ICF experiments are inferred from the broadening of primary neutron spectra. Directional motion (?ow) of the fuel at burn also impacts broadening and will lead to arti?cially in?ated “Tion” values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion. We report on intentionally asymmetrically driven experiments at the OMEGA laser facility designed to test the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded ?ows. Contrasted to CHIMERA and xRAGE simulations, the measurements demonstrate how all asymmetry seeds have to be considered to fully capture the ?ow ?eld in an implosion. In particular, ?ow induced by the stalk that holds the target is found to interfere with the seeded asymmetry. A substantial stalk-seeded asymmetry in the areal density of the implosion is also observed.
关键词： CHIMERA,xRAGE simulations,OMEGA laser facility,inertial con?nement fusion,ion temperatures,low-mode asymmetries
更新于2025-09-23 15:21:21
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[IEEE 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Cartagena des Indias, Colombia (2018.9.10-2018.9.14)] 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - EM Wave Scattering by a Window on a Wall
摘要： Electromagnetic wave scattering by a window on a building wall has been analyzed here as plane wave scattering by a dielectric slab in a thick conducting screen. High frequency asymptotic ray method is utilized for this analysis. Geometrical Theory of Diffraction has been used to obtain the diffracted fields by the edges of the aperture, then ray-mode conversion technique has been applied to get the modal field inside the slit region in order to consider the modal coupling and the re-radiation field. The validity of our formulation has been first tested by comparing the results with those obtained by the Kobayashi Potential method for the relatively narrow slit aperture cases. Then the various numerical calculation results have been made to show the effects of the wall and window thickness, and window’s glasses for practical wireless mobile communication frequencies.
关键词： ray-mode conversion,GTD,EM scattering,thick slit,window
更新于2025-09-23 15:21:21
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Recent progress in all-fiber non-Gaussian optical beam shaping technologies
摘要： Rapid development of fiber lasers are being followed by wide ranges of applications in laser processing technologies. One of the key parameters to determine the laser-matter interaction is beam shape and there have been intense research activities on beam shaping using bulk-optics. However, fiber optic solutions would take clear advantages over bulk-optics especially for fiber laser sources in terms of the beam conversion efficiency, the throughput power, and the compact footprint. In this article, all-fiber optical beam shaping technologies are reviewed and they are categorized as the phase front modification on the fiber facet, the surface plasmonics on fiber, all-fiber Fourier transformation, and multimode interference. Their physical principles, beam shaping capability, and some of the novel applications are explained
关键词： Phase front engineering,Laser beam,Surface plasmon polariton,Beam Shaping,Multimode Interference,Fourier Transform,Fiber Optics,Single mode optical fiber
更新于2025-09-23 15:21:21
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823 mA/mm drain current density and 945 MW/cm2 Baliga’s figure of merit enhancement-mode GaN MISFETs with a novel PEALD-AlN/LPCVD-Si3N4 dual gate dielectric
摘要： In this letter, we demonstrate a novel PEALD-AlN/LPCVD-Si3N4 dual gate dielectric employed in enhancement-mode GaN MISFETs, where the gate recess is fabricated based on our proposed self-terminating gate recess etching technique using GaN cap layer as recess mask. By using LPCVD-Si3N4 and PEALD-AlN dual gate dielectric layer, the devices exhibit a high quality gate dielectric and a good GaN channel interface, yielding a high gate swing up to 18V and a high channel effective mobility of 137 cm2/V?s at such high gate bias. Thus, the fabricated devices feature a high maximum drain current density of 823 mA/mm, a threshold voltage of 2.6 V, an on-resistance of 7.4 Ω?mm, and an ON/OFF current ratio of 108 with gate-drain distance of 2 μm. Meanwhile, a high OFF-state breakdown voltage of 1290 V is achieved with 10 μm gate-drain distance. The corresponding specific on-resistance is as low as 1.76 mΩ?cm2, leading to a high Baliga’s ?gure of merit of 945 MW/cm2.
关键词： self-terminating etching,enhancement-mode GaN MISFETs,plasma-enhanced atomic layer deposition (PEALD) AlN,LPCVD Si3N4
更新于2025-09-23 15:21:21
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Gate Conduction Mechanisms and Lifetime Modeling of p-Gate AlGaN/GaN High-Electron-Mobility Transistors
摘要： The gate conduction mechanisms in p-gallium nitride (GaN)/AlGaN/GaN enhancement mode transistors are investigated using temperature-dependent dc gate current measurements. In each of the different gate voltage regions, a physical model is proposed and compared to experiment. At negative gate bias, Poole–Frenkel emission (PFE) occurs within the passivation dielectric from gate to source. At positive gate bias, the p-GaN/AlGaN/GaN “p-i-n” diode is in forward operation mode, and the gate current is limited by hole supply at the Schottky contact. At low gate voltages, the current is governed by thermionic emission with Schottky barrier lowering in dislocation lines. Increasing the gate voltage and temperature results in thermally assisted tunneling (TAT) across the same barrier. An improved gate process reduces the gate current in the positive gate bias region and eliminates the onset of TAT. However, at high positive gate bias, a sharp increase in current is observed originating from PFE at the metal/p-GaN interface. Using the extracted conduction mechanisms for both devices, accurate lifetime models are constructed. The device fabricated with the novel gate process exhibits a maximum gate voltage of 7.2 V at t1% = 10 years.
关键词： time-dependent breakdown (TDB),p-GaN gate,high-electron-mobility transistor (HEMT),enhancement mode,gallium nitride (GaN),Conduction mechanism
更新于2025-09-23 15:21:21
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[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - A Multi-Carrier Signals Generation Based on DPMZM In Parallel for THz Communication system
摘要： In this paper, a multi-carrier THz signals generation scheme is proposed and demonstrated. The scheme is based on DPMZM (dual-parallel Mach-Zehnder modulator) in parallel and recirculating frequency shifter (RFS). By optimizing all the sub-modulators embedded in the RFS, the multi-carrier signals with double frequency interval are generated. A theoretical analysis and simulation experiment is developed, the scheme can generate 20 carriers with 0.1THz frequency interval, and the side-mode suppression ratio (SMSR) is over 25dB.
关键词： side-mode suppression ratio,recirculating frequency shifter,multi-carrier THz signals,DPMZM
更新于2025-09-23 15:21:21
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Dual-Band Filtering Balun Based on Dual-Mode Dielectric Resonator
摘要： In this paper, a dual-mode dielectric resonator (DR) is investigated and utilized to design filtering balun with dual-band response. The properties of the dual-mode DR are analyzed in detail. According to the field distributions, the two modes can be simultaneously extracted as out-of-phase signals for differential applications. A dual-band filtering balun is designed, fabricated and measured, showing good performance of amplitude balance and 180o phase difference. Good agreement can be obtained between their respective simulated and measured results.
关键词： filtering balun,dual-band,dual-mode dielectric resonator (DR)
更新于2025-09-23 15:21:21
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[IEEE 2018 IEEE International Conference on Intelligence and Safety for Robotics (ISR) - Shenyang, China (2018.8.24-2018.8.27)] 2018 IEEE International Conference on Intelligence and Safety for Robotics (ISR) - Experimental study on operator-based integral sliding mode robust nonlinear control for WPT systems
摘要： In our previous research on wireless power transfer systems, an operator-based sliding mode control design was proposed to regulate the output voltage. However, the steady-state error exists in the nonlinear control system. In this paper, an operator-based integral sliding mode robust nonlinear control design scheme is proposed to eliminate the steady-state error in the wireless power transfer system. Besides, the robust stability is guaranteed by using robust right coprime factorization approach. Results of simulations and experiments are presented to prove the effectiveness of the proposed control design scheme.
关键词： operator-based control,robust nonlinear control,steady-state error,sliding mode control,wireless power transfer
更新于2025-09-23 15:21:21
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Application and Extension of Vertical Intensity Lower-Mode in Methods for Target Depth-Resolution with a Single-Vector Sensor
摘要： In this paper, based on the reactive component of the vertical intensity, the method for target depth resolution has been improved. In the previous existing research results, using the reactive component of vertical intensity, the research objects for target depth resolution in shallow water, can only be the targets whose frequencies can only excite the ?rst two normal modes, and the depth of targets whose frequencies excite more than two normal modes cannot be correctly identi?ed. The basic idea of the improved method is to classify targets on the foundation of the lower-mode correlation quantity of the vertical intensity. Based on the improved method, we can realize depth resolution of the targets whose frequency can excite the ?rst three normal modes so as to effectively expand the working band useful for target depth resolution. Finally, we can realize the three-dimensional target depth resolution so as to distinguish the aerial, surface and underwater targets. The feasibility of the algorithm is veri?ed by simulation and experimental data processing.
关键词： ?rst three normal modes,improved method,lower-mode correlation quantity,Monte Carlo,depth resolution
更新于2025-09-23 15:21:21