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[IEEE 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Pitesti, Romania (2019.6.27-2019.6.29)] 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Design of an LED-based solar spectrum simulator for porphyrin dye-sensitized solar cell characterization
摘要： This paper presents the design considerations for a special solar spectrum simulator, based on LED technology, specifically conceived for the characterization of porphyrin-based dye-sensitized solar cells.
关键词： solar spectrum,photovoltaics,solar simulator,DSSC,LED
更新于2025-09-23 15:21:01
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Updated Fast Solution for Quasi-Optical Beam Waveguides With Tilted FFT Beam Propagator
摘要： An updated fast solution in modeling quasi-optical beam waveguides is reported, where several mirror reflectors are utilized for the beam transformation. The fast Fourier transform Poynting vector ray tracing between virtual apertures (FFT-PVVAs) algorithm has been introduced and applied in modeling the reflected beam, based on the FFT-accelerated beam propagator between parallel apertures, and the Poynting vector ray tracing for the mirror reflection. However, for designing and optimizing a beam path with multireflectors, it is desired that the accumulated precision loss due to the Poynting vector ray tracing can be further reduced. As a modification, angular spectrum transform-based beam propagator between oblique apertures is introduced, so as to reduce the ray tracing path length. The improved method is named as FFT-PVVA-tilted propagation (FFT-PVVA-TP). As validation, beam propagation in a four-mirror beam waveguide is simulated by FFT-PVVA, FFT-PVVA-TP, and physical optics integration. Numerical results suggest that FFT-PVVA-TP provides clearly better accuracy after four times of beam reflection.
关键词： Angular spectrum (AS),Poynting vector,beam propagation,quasi-optical (QO) beam waveguides
更新于2025-09-23 15:21:01
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THz photodetector using sideband-modulated transport through surface states of a 3D topological insulator
摘要： The transport properties of the surface charge carriers of a three dimensional topological insulator under a terahertz (THz) field along with a resonant double barrier structure is theoretically analyzed within the framework of Floquet theory to explore the possibility of using such a device for photodetection purposes. We show that due to the contribution of elastic and inelastic scattering processes in the resulting transmission, side-bands are formed in the conductance spectrum. This side band formation is similar to the side-bands formation in cavity transmission spectra in an optical cavity and this information can be used to detect the frequency of unknown THz radiation. The dependence of the conductance on the bias voltage, the effect of THz radiation on resonances and the influence of zero energy points on the transmission spectrum are also discussed.
关键词： THz radiation,Floquet theory,surface states of topological insulators,side bands in transmission spectrum
更新于2025-09-23 15:21:01
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Superconducting one-dimensional photonic crystal with coupled semiconductor defects
摘要： We investigate the impact of the insertion of a semiconductor defect on the transmittance spectrum of a one-dimensional photonic crystal composed by alternating layers of superconducting materials. We report that the effect of the insertion of the semiconductor defect originates a defective mode in the photonic band gap that exhibits a shift towards long-wavelength regimes. Unexpectedly, for high values of temperatures, it is observed that the defective mode reduces its confinement as well as influences the optical response of the photonic crystal rather than the pressure. We also extend our analysis to the case of two coupled defects of GaAs, and it is studied the effect of the relative distance between these two defects. Our numerical results reveal that the defective mode has a significant reduction in its quality factor as well as it displays an asymmetry in the transmittance spectrum when the defects are close to each other.
关键词： Transfer matrix method,Defect mode,Semiconductor,Transmittance spectrum,One-dimensional photonic crystal,Superconductor
更新于2025-09-23 15:21:01
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Different material modifications in laser-induced damage of optical films in air and vacuum environments
摘要： A combination study of material modifications for the catastrophic laser-induced damage by 12 ns, 1064 nm laser pulse irradiation was investigated in air and vacuum environments. The samples were observed by optical microscope, scanning electron microscopy, laser micro-Raman spectroscopy, photoluminescence spectrum; moreover 2D numerical calculations were performed. According to our results, vacuum pumping induced higher laser field intensities, accompanying with more absorption of laser energy in the laser-induced damage process. All of these resulted in the material melting and subsequent re-solidification in the laser-damaged core in vacuum. While, in the air conditions, plasma expanding due to material heating and associated thermal expansion induced a large stress field, which caused the material deformation and formation of delamination and crack in the laser-damage region.
关键词： Vacuum,Photoluminescence spectrum,Laser-induced damage,Laser micro-Raman spectroscopy
更新于2025-09-23 15:21:01
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Multilayer Non-interacting Dielectric Metasurfaces For Multiwavelength Metaoptics
摘要： Metasurfaces provide a versatile platform for manipulating the wavefront of light using planar nanostructured surfaces. Transmissive metasurfaces, with full 2π phase control, are a particularly attractive platform for replacing conventional optical elements due to their small footprint and broad functionality. However, the operational bandwidth of metasurfaces has been a critical limitation and is directly connected to either their resonant response or the diffractive dispersion of their lattice. While multiwavelength and continuous band operation have been demonstrated, the elements suffer from either low efficiency, reduced imaging quality, or limited element size. Here, we propose a platform that provides for multiwavelength operation by employing tightly spaced multilayer dielectric metasurfaces. As a proof of concept, we demonstrate a multiwavelength metalens doublet (NA=0.42) with focusing efficiencies of 38% and 52% at wavelengths of 1180 nm and 1680 nm, respectively. We further show how this approach can be extended to three wavelength metalenses as well as a spectral splitter. This approach could find applications in fluorescent microscopy, digital imaging, and color routing.
关键词： Multiwavelength metalens,spectrum splitter,metasurface doublet,polarization-insensitive
更新于2025-09-23 15:21:01
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Novel report on structural, optical and electrical investigation into brucinium 4-methyl-3-nitrobenzoate 0.5 hydrate single crystal: a promising material for high-power laser, ultrahigh cooling, sensor and detector applications
摘要： A new brucinium 4-methyl-3-nitrobenzoate 0.5 hydrate (B4M3NB0.5H) NLO single crystal was harvested from saturated solution by solvent evaporation method. Crystal system and symmetric type of B4M3NB0.5H compound were analyzed by structure analysis. Linear optical parameters of title compound were discussed in detail by UV–visible analysis. Lifetime values of the molecule were quanti?ed by ?uorescence study, and it con?rms the good crystalline perfection of the grown crystal. The SHG ef?ciency is 5.11 times superior to the KDP material. By utilizing Nd:YAG laser as an input, SLDT measurement of the crystal was done. The grown crystal has good crystalline nature which is analyzed by HRXRD study. Dielectric behavior of B4M3NB0.5H crystal was discussed in detail. With the help of theoretical approach, few of the solid-state parameters were calculated and listed. Piezoelectric charge coef?cient and piezovoltage were calculated to be 4.5 p C/N and 0.0417 p V m/N, respectively. The TGA and DTA spectrum con?rms that the title compound is thermally stable up to 101 °C.
关键词： piezoelectric charge coefficient,brucinium 4-methyl-3-nitrobenzoate,fluorescence study,solvent evaporation method,SHG efficiency,HRXRD study,NLO single crystal,Nd:YAG laser,dielectric behavior,UV–visible analysis,TGA and DTA spectrum
更新于2025-09-23 15:21:01
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Broadband Cognitive Radio Enabled by Photonics
摘要： Cognitive radio is considered as a possible disruptive force to improve the spectral resource efficiency through sensing and interacting with the environment. Traditional electrical technologies to implement the cognitive radio face challenges in terms of bandwidth, resolution, and speed. In this paper, the concept and architecture of broadband cognitive radio systems enabled by photonics are proposed. Key microwave photonic techniques for the architecture are reviewed, including the photonics-based spectrum sensing, the photonic arbitrary waveform generation, the photonics-based self-interference cancellation processing, and the microwave photonic dechirp processing and radar imaging. A preliminary demonstration of a cognitive radar system enabled by photonics is performed. The future possible research directions on this topic are discussed.
关键词： Cognitive radio,spectrum sensing,microwave photonics,radar imaging,self-interference cancellation,waveform generation
更新于2025-09-23 15:21:01
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THE EFFECTS OF CONTINUOUS LIGHTING (CL) METHOD ON THE GROWTH DEVELOPMENT OF BRASSICA CHINENSIS FOR LED PLANT FACTORY IN WSN APPLICATION
摘要： This study was performed to investigate the best practise on using LED light for optimum growth of Brassica Chinensis and reduce turn around time at different kind of photoperiod study utilizing Wireless Sensor Network (WSN) technology as remote monitoring system. Growth performance of Brassica Chinensis under two different wavelengths (blue and red) 16:4 as light source has been used to determine plant growth performance and phytochemicals aspect of plant characteristics. Two experiments were conducted which is the pulse treatment (1 hour light and 1 hour dark) and continuous light (CL) photoperiod treatment in both trials. Observation such as leaves count, height, dry weight and chlorophy I & ll of both plants were analysed. It was noted that the CL photoperiod has significant effect on overall growth performance and remarkably lead to improve the efficiency of the plant factory. In order to reason on data and monitor the environmental parameters of the plant factory, an intelligent system using embedded system has been developed to automate the LED control and manipulation. The result shows that the system is stable and has referential significantly in the area of plant factory or indoor farming system.
关键词： LED Light Spectrum,Intelligent Control Farming,Continuous Lighting,Sensor,Indoor Farming,Wireless Sensor Network,Plant Factory
更新于2025-09-23 15:21:01
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A RMSA algorithm for elastic optical network with a tradeoff between consumed resources and distance to boundary
摘要： Elastic optical network (EON) has been a promising technology for the next generation of core transport networks, because it can support flexible spectrum assignment. Routing, modulation and spectrum assignment (RMSA) is one of the key issues in EON. In this paper, two indexes are considered during the spectrum assignment process, number of consumed resources R and distance to boundary I. Minimizing R means using the least resources to establish a connection while minimizing I implies that remainder idle resources are more lumped after a connection is established. Both of them can reduce blocking probability of network. However, optimizations of R and I are sometimes contradictory, so we propose three policies to make a tradeoff between them, which are R I I R policy sets I as the optimizing objective. as the chief one; the I policy can get the best Simulations are taken on the NSF-Net and UBN topologies, which show that the +R performance in most cases. We further compare the +R I policy with two existing well-performed algorithms, the First-Last-Fit algorithm and the Block-Assignment algorithm. Simulation results reveal that blocking probability of the +R I . The R I: policy takes R as the primary objective while the I R: I policy is far less than that of the comparative objects. I policy takes a linear combination and +R +R α I ) αR (1 + ? : :,
关键词： Blocking probability,Routing and spectrum assignment,RMSA,Elastic optical network (EON)
更新于2025-09-23 15:21:01