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 Electron diffraction (3)
 Photonic bandgap calculations (2)
 Electromagnetic optics (2)
 Photonic crystals (2)
 Indium tin oxide (1)

 Heat transfer (1)
 Lambertine angular distribution (1)
 Electron pulse (1)
 Electric space charge (1)
 Electron pulses (1)
 Camera systems (1)
 Electric fields (1)
 Debye temperature (1)
 Electron beams (1)
 Drift distance (1)
 Electron conduction (1)
 Electron pulse broadening (1)
 Localized surface plasmon resonance (1)
 Finite difference time domain (1)
 Holey fibers (1)
 Energy spreads (1)
 Electron mobility (1)
 Electron energy levels (1)
 Femtosecond electron pulse compression (1)
 Electron drift (1)
 Metallic thin films (1)
 DebyeWaller factors (1)
 Coated glass substrates (1)
 Crystal structures (1)
 Microoptics (1)
Articles 1  8 of 8
FullText Articles in Physics
Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By DarkField Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, XiaoHong Nancy Xu, Hani E. ElsayedAli
Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By DarkField Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, XiaoHong Nancy Xu, Hani E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and diskshaped Ag NP pairs with varying interparticle distance is studied using darkfield optical microscopy and spectroscopy (DFOMS). Disk, square, and triangularshaped Ag NPs were fabricated on indium tin oxidecoated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shapedependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in ...
Loss And Dispersion Analysis Of Microstructured Fibers By FiniteDifference Method, Shangping Guo, Feng Wu, Sacharia Albin, Hsiang Tai, Robert S. Rogowski
Loss And Dispersion Analysis Of Microstructured Fibers By FiniteDifference Method, Shangping Guo, Feng Wu, Sacharia Albin, Hsiang Tai, Robert S. Rogowski
Electrical & Computer Engineering Faculty Publications
The dispersion and loss in microstructured fibers are studied using a fullvectorial compact2D finitedifference method in frequencydomain. This method solves a standard eigenvalue problem from the Maxwell’s equations directly and obtains complex propagation constants of the modes using anisotropic perfectly matched layers. A dielectric constant averaging technique using Ampere’s law across the curved media interface is presented. Both the real and the imaginary parts of the complex propagation constant can be obtained with a high accuracy and fast convergence. Material loss, dispersion and spurious modes are also discussed.
Photonic Band Gap Analysis Using FiniteDifference FrequencyDomain Method, Shangping Guo, Feng Wu, Sacharia Albin
Photonic Band Gap Analysis Using FiniteDifference FrequencyDomain Method, Shangping Guo, Feng Wu, Sacharia Albin
Electrical & Computer Engineering Faculty Publications
A finitedifference frequencydomain (FDFD) method is applied for photonic band gap calculations. The Maxwell’s equations under generalized coordinates are solved for both orthogonal and nonorthogonal lattice geometries. Complete and accurate band gap information is obtained by using this FDFD approach. Numerical results for 2D TE/TM modes in square and triangular lattices are in excellent agreements with results from plane wave method (PWM). The accuracy, convergence and computation time of this method are also discussed.
Electron Pulse Broadening Due To Space Charge Effects In A Photoelectron Gun For Electron Diffraction And Streak Camera Systems, BaoLiang Qian, Hani E. ElsayedAli
Electron Pulse Broadening Due To Space Charge Effects In A Photoelectron Gun For Electron Diffraction And Streak Camera Systems, BaoLiang Qian, Hani E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
The electron pulse broadening and energy spread, caused by space charge effects, in a photoelectron gun are studied analytically using a fluid model. The model is applicable in both the photocathodetomesh region and the postanode electron drift region. It is found that space charge effects in the photocathodetomesh region are generally unimportant even for subpicosecond pulses. However, because of the long drift distance, electron pulse broadening due to space charge effects in the drift region is usually significant and could be much larger than the initial electron pulse duration for a subpicosecond electron pulse. Space charge effects can also lead ...
Acceleration Element For Femtosecond Electron Pulse Compression, BaoLiang Qian, Hani E. ElsayedAli
Acceleration Element For Femtosecond Electron Pulse Compression, BaoLiang Qian, Hani E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
An acceleration element is proposed for compressing the electron pulse duration in a femtosecond photoelectron gun. The element is a compact metal cavity with curvedshaped walls. An external voltage is applied to the cavity where a special electric field forms in such a way that the slow electrons in the electron pulse front are accelerated more than the fast electrons, and consequently the electron pulse duration will be compressed. The distribution of the electric field inside the acceleration cavity is analyzed for the geometry of the cavity. The electron dynamics in this acceleration cavity is also investigated numerically. Numerical results ...
Reflection HighEnergy ElectronDiffraction Study Of Melting And Solidification Of Pb On Graphite, Z. H. Zhang, P. Kulatunga, H. E. ElsayedAli
Reflection HighEnergy ElectronDiffraction Study Of Melting And Solidification Of Pb On Graphite, Z. H. Zhang, P. Kulatunga, H. E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
The melting and solidification of Pb thin films on pyrolytic graphite are investigated in situ by reflection highenergy electron diffraction. Thin films with thicknesses of 4150 monolayers are investigated. The surface morphology of the thin films were studied by scanning electron microscopy. Superheating of the Pb thin films by 4±2 to 12±2 K is observed from diffraction intensity measurements. Upon cooling the substrate, the Pb on graphite is seen to supercool by ∼69±4 K.
Surface Debye Temperature Measurement With Reflection HighEnergy Electron Diffraction, H. E. ElsayedAli
Surface Debye Temperature Measurement With Reflection HighEnergy Electron Diffraction, H. E. ElsayedAli
Electrical & Computer Engineering Faculty Publications
Measurement of the surface meansquare atomic vibrational amplitude, or equivalently the surface Debye temperature, with reflection highenergy electron diffraction is discussed. Lowindex surfaces of lead are used as examples. Particular details are given about the temperaturedependent diffraction pattern of Pb(100) in the DebyeWaller region. The use of reflection highenergy electron diffraction for measurement of the substrate surface temperature in thinfilm deposition chambers is suggested. © 1996 American Institute of Physics.
Direct Measurements Of The Transport Of Nonequilibrium Electrons In Gold Films With Different Crystal Structures, T. Juhasz, H. E. ElsayedAli, G. O. Smith, C. Suárez, W. E. Bron
Direct Measurements Of The Transport Of Nonequilibrium Electrons In Gold Films With Different Crystal Structures, T. Juhasz, H. E. ElsayedAli, G. O. Smith, C. Suárez, W. E. Bron
Electrical & Computer Engineering Faculty Publications
The transport of femtosecondlaserexcited nonequilibrium electrons across polycrystalline and singlecrystalline gold films has been investigated through timeofflight measurements. The thicknesses of the films range from 25 to 400 nm. Ballistic electrons as well as electrons interacting with other electrons and/or with the lattice have been observed. The ballistic component dominates the transport in the thinner films, whereas the interactive transport mechanism is dominant at the upper end of the thickness range. A slower effective velocity of the interactive component is observed in the polycrystalline samples, and is assumed to arise from the presence of grain boundaries. The reflection coefficient ...