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Plasmonic nickel nanoparticles decorated on to LaFeO3 photocathode for enhanced solar hydrogen generation
摘要： Plasmonic Ni nanoparticles were incorporated into LaFeO3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70e100 nm for Surface Plasmon Resonance (SPR) enhancement.
关键词： LaFeO3,Finite difference time domain,Surface plasmon resonance,Ni nanoparticle,Photocathode,Photoelectrochemical water splitting
更新于2025-10-22 19:40:53
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Orientation-Dependent THz Response of <i>m</i> -Plane Sapphire Substrate by Polarization-Sensitive THz Time Domain Spectroscopy
摘要： The dielectric response of m-plane sapphire (m-sapphire) substrates in the terahertz (THz) frequency is investigated using polarized-sensitive femto-second THz time-domain spectroscopy. We examined the transmitted THz time-domain waveforms with respect to the parallel-polarized THz field by rotating phi angle of m-sapphire substrates. The THz amplitude significantly decreased at the azimuth angle of 0°, 90°, and 180° with roughly equal amplitudes and no propagation time delay. The time delay of 480 fs in the THz pulse oscillations was observed between the azimuth angle of 45° and 90°, possibly due to the birefringence of nonpolar m-sapphire substrate. Strong THz field absorptions around ～1 THz frequency at azimuth angles of every 90° could be attributed to low-frequency phonon modes.
关键词： Sapphire,Birefringence,Time-Domain Spectroscopy,THz
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Anisotropic HIE-FDTD Scheme to Analyze Magnetically Biased Graphene
摘要： An anisotropic hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) scheme is developed to investigate the magnetically biased graphene. The anisotropic conductivity of the graphene is calculated in this scheme. The time increment in proposed method is not related with the fine meshes in the graphene sheet, so this scheme has much higher simulation efficiency than the conventional FDTD scheme.
关键词： magnetically biased,graphene,Terahert time-domain finite-difference
更新于2025-09-23 15:23:52
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Calculation of the Transient Electric Field Transmitted in a Lossy Medium Radiated by an Equivalent GPR Dipole Antenna
摘要： The paper deals with the characterization of electric field radiated by a GPR antenna and transmitted into a lossy medium. Realistic bow-tie GPR antenna is modeled as an equivalent dipole antenna with current distribution governed by Hallen integral equation. Electric field transmitted into a lossy medium is determined using Boundary Element formalism for the solution of field integral formulas. Electric field distribution at a certain depth is calculated using this procedure.
关键词： transmitted electric field,time domain analysis,lossy medium,equivalent dipole antenna
更新于2025-09-23 15:23:52
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Preparation and optical properties of angle-dependent photonic crystals based on multi-layer films
摘要： The CreSiO2 photonic crystals, featured with two-dimensional structure and optical variation, was prepared by magnetron sputtering and electron beam lithography method. The finite difference time domain method (FDTD) is used to study the light-modulated characteristics of photonic crystals. Hue difference (⊿H) was used to evaluate the optical variations of photonic crystals, and bigger ⊿H indicates stronger angle dependency of color variation. Various parameters are analyzed for their impact upon ⊿H, including hole geometry (radium, r), hole gap (distance between the centers of two circles, d) and hole depth (h). The results matched the ones from simulation. Carbon quantum dots and up-conversion nanocrystals NaYF4 were inserted into the photonic crystals, and testing results of these doped crystals showed optical variation of fluorescence in the UV and IR region.
关键词： Finite difference time domain,Multi-layer films,Photonic crystal,Optical variability
更新于2025-09-23 15:23:52
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Numerical study of nanoscale biosensor based on surface plasmon polariton propagation in Mach-Zehnder interferometer structure
摘要： In this paper, we numerically investigate a nanoscale plasmonic biosensor based on Mach-Zehnder interferometry. The operation of Mach-Zehnder interferometer (MZI) biosensor is examined based on two methods. In the first method, in which the transmission of surface plasmon polariton (SPP) modes is investigated under different refractive indices of sample medium as well as different dimensions, the best transmission rate achieved about 56.6% which is resulted by refractive index variation about 0.045 for the length 12 μm and width 80 nm of the gold layer. Also, the sensitivity, figure of merit (FOM) and quality factor (Q-factor) of MZI are examined for different geometries by utilizing the alternative method. It is realized that for the constant length, increasing the thickness of gold layer has significantly led to increased Q-factor and FOM. On the other hand, considering fixed thickness of the Au layer and three different lengths, the major outcome is that as the length of biosensor increases, the sensitivity, Q-factor as well as FOM follow an upward trend. Finally, inserting two distinct additional gold layers on top of the main gold layer, resulted in an extreme increase for the sensitivity and FOM of the plasmonic MZI biosensors with respect to the MZI biosensor without additional layer.
关键词： Plasmonic biosensor,Surface plasmon polariton (SPP),Mach-Zehnder interferometer (MZI),Finite difference time domain (FDTD)
更新于2025-09-23 15:23:52
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Surface plasmon resonance on blue GaN-based VCSEL with Al-grating
摘要： Based on the research of surface plasmon (SP) applied to Vertical-Cavity Surface-Emitting Lasers (VCSEL), we proposed a new 465 nm GaN-based VCSEL to enhance illumination by deposit Al rectangular grating onto p-i-n layer. Meanwhile, an increase in the e?ective radiated power was obtained by the control of a surface plasmon mode, which depends strongly on the structural parameters such as material, period, depth and dipole location. Compared to conventional structure, we have a 30% improvement in e?ective radiated power. Such advantages make surface Al-grating be an alternative low-cost and simple technique used in SP-coupled VCSEL for the blue range.
关键词： Finite-di?erence time-domain method,Metal grating,Surface plasmon,Vertical-cavity surface-emitting laser (VCSEL)
更新于2025-09-23 15:23:52
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Inspecting human colon adenocarcinoma cell lines by using terahertz time-domain reflection spectroscopy
摘要： Techniques to inspect and analyze human colorectal cancer cell lines by using terahertz time-domain attenuated total reflection spectroscopy (THz TD-ATR) were investigated. The characteristics of THz absorption spectra of two colorectal cancer cell lines DLD-1 and HT-29 in aqueous solutions with different concentrations were studied. Different spectral features were observed compared to normal cell line. Identification results based on different parameters including absorption coefficient, refractive index, real and imaginary parts of complex permittivity, dielectric loss tangent were discussed. This research may be promising for quick and instant inspection of liquid samples by using THz time-domain spectroscopy in medical applications.
关键词： Absorption coefficient,Dielectric loss tangent,Terahertz time-domain attenuated total reflection spectroscopy,DLD-1 cell line,Cancer identification,HT-29 cell line
更新于2025-09-23 15:23:52
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UPML-ABC of dispersive materials for the unconditionally stable 2-D WLP-FDTD method
摘要： In this paper, uniaxial anisotropic perfectly matched layer (UPML) absorbing boundary condition (ABC) of dispersive materials is presented for 2-D finite-difference time-domain (FDTD) method with weighted Laguerre polynomials (WLP). Taking advantage of the auxiliary differential equation (ADE) technique, our proposed algorithm avoids not only the complicated formulations but also the convolution integral. Using ADE scheme, the relationship between field components and auxiliary differential variables is derived in Laguerre domain. Substituting auxiliary differential variables into UPML-ABC, the electric field E of order q can be expressed directly by magnetic field H in Laguerre domain. Inserting magnetic field H of order q into electric field, and using central difference scheme, the formulations of uniaxial anisotropic dispersive media PML are obtained. One numerical example of wave propagation in 2-D dispersive materials is simulated. Numerical results validate the efficiency of the presented method.
关键词： finite-difference time-domain (FDTD),weighted laguerre polynomials (WLP),uniaxial anisotropic dispersive materials,perfectly matched layer (PML),Auxiliary differential equation (ADE)
更新于2025-09-23 15:23:52
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Finite-Difference Time-Domain Modeling for Electromagnetic Wave Analysis of Human Voxel Model at Millimeter-Wave Frequencies
摘要： The finite-difference time-domain (FDTD) modeling of a human voxel model at millimeter-wave (mmWave) frequencies is presented. It is very important to develop the proper geometrical and electrical modeling of a human voxel model suitable for accurate electromagnetic (EM) analysis. Although there are many human phantom models available, their voxel resolution is too poor to use for the FDTD study of EM wave interaction with human tissues. In this paper, we develop a proper human voxel model suitable for mmWave FDTD analysis using the voxel resolution enhancement technique and the image smoothing technique. The former can improve the resolution of the human voxel model and the latter can alleviate staircasing boundaries of the human voxel model. Quadratic complex rational function is employed for the electrical modeling of human tissues in the frequency range of 6–100 GHz. Massage passing interface-based parallel processing is also applied to dramatically speed up FDTD calculations. Numerical examples are used to illustrate the validity of the mmWave FDTD simulator developed here for bio electromagnetics studies.
关键词： human tissue,electromagnetic wave,Doppler radar,dispersion model,bioelectromagnetics,Finite-difference time-domain (FDTD) method,parallel processing
更新于2025-09-23 15:23:52