477 research outputs found
Passive and Thermo-Optic Characterization of Long-Range Surface Plasmon-Polariton Structures in CYTOP
No full textLong-range surface plasmon-polariton waveguides fabricated of gold, cladded with CYTOP, designed to be 5μm wide and 35nm thick, were modelled and fabricated by other researchers and tested by the author. In passive measurements, cutback curves were drawn and S-bends, Y-junctions, Mach-Zehnder interferometers, and couplers were tested. Results show that the fabricated waveguide thicknesses are inconsistent and thinner than designed, and improvement of their fabrication quality is necessary. In thermo-optic measurements, electric currents were injected heating the waveguides and changing the refractive index of the claddings. Electromigration were characterized and the conclusion was that the waveguides can work under the current density 70GA/m2. Mode extinction experiments were made and as one waveguide was repeatedly tested its mode extinction threshold gradually decreased due to heat accumulation and CYTOP glass-transition. 2.5mA was safe to prevent mode extinction in the first 12 experiments. The optical response time was also measured and discussed
Passive and Thermo-Optic Characterization of Long-Range Surface Plasmon-Polariton Structures in CYTOP
No full textLong-range surface plasmon-polariton waveguides fabricated of gold, cladded with CYTOP, designed to be 5μm wide and 35nm thick, were modelled and fabricated by other researchers and tested by the author. In passive measurements, cutback curves were drawn and S-bends, Y-junctions, Mach-Zehnder interferometers, and couplers were tested. Results show that the fabricated waveguide thicknesses are inconsistent and thinner than designed, and improvement of their fabrication quality is necessary. In thermo-optic measurements, electric currents were injected heating the waveguides and changing the refractive index of the claddings. Electromigration were characterized and the conclusion was that the waveguides can work under the current density 70GA/m2. Mode extinction experiments were made and as one waveguide was repeatedly tested its mode extinction threshold gradually decreased due to heat accumulation and CYTOP glass-transition. 2.5mA was safe to prevent mode extinction in the first 12 experiments. The optical response time was also measured and discussed
Bloch Long-Range Surface Plasmon Polaritons on Metal Stripe Waveguides on a Multilayer Substrate
No full textPlasmonic optoelectronic devices and metasurfaces
Get PDFWe report recent progress on optoelectronic devices and metasurfaces involving surface plasmons, enabled by metal-oxide-semiconductor (MOS) structures on Si and on epsilon-near-zero materials. We discuss electrically tuneable metasurfaces, high-speed electro-absorption modulators, and reflection modulators. Hot carriers created by the absorption of plasmons in metallic nanostructures on MOS structures are also discussed as they lead to novel device physics that open the door to new device concepts
CO2 adsorption and activation on Ag(111) surfaces in the presence of surface charge density: A static gas phase DFT study
No full textThe CO2 reduction reaction on Ag in the presence of surface plasmons are of strong interest in photocatalysis. Here, two Density Functional Theory (DFT) approaches are proposed to localize charges at the Ag surface to mimic surface plasmon excitation. These calculations predict charge localization at the outermost surface layer, a result confirmed via light excitation at the plasmon resonance modeled by Density Functional Tight Binding Hamiltonian (DFTB) theory. The CO2 (gas) reduction initial steps are studied by DFT models showing that bonded species can be created on top of an Ag-atom in the presence of extra charges. A second CO2 molecule can assist the first molecule, decreasing the charge carrier density requirement for CO2 reduction bonded species. A Mo lecular Dynamics (MD) study shows a possible interaction among CO2 molecule. These results show that a static DFT simulation can mimic charge localization resulting from surface plasmon effects, thus enabling studies on surface plasmon-enhanced chemical reactions, paving the way for future time-dependent (TD) studies.Fil: Sandoval, Mario German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina. University of Ottawa; CanadáFil: Walia, Jaspreet. University of Ottawa; CanadáFil: Houache, Mohamed S. E.. National Research Council. Energy, Mining and Environment Research Centre; CanadáFil: Abu Lebdeh, Yaser. National Research Council. Energy, Mining and Environment Research Centre; CanadáFil: Berini, Pierre. University of Ottawa; CanadáFil: Faccio, Ricardo. Universidad de la República; UruguayFil: Weck, Arnaud. University of Ottawa; Canad
Modeling and Characterization of Antireflection Coatings with Embedded Silver Nanoparticles for Silicon Solar Cells
No full textA high-efficiency power amplifier integrated with a planar transmitting antenna.
No full textIn this thesis, the coplanar-waveguide-fed aperture-coupled patch antenna is studied for the purpose of integration with a high efficiency power amplifier. A high efficiency power amplifier is designed via experimental determination of the loads required at the output of a transistor in order to maximise its efficiency. For this purpose, an active multi-harmonic load-pull system capable of independently varying the fundamental-frequency, second-harmonic-frequency and third-harmonic-frequency reflection coefficients seen at the output of a transistor is constructed. Six-port reflectometers are designed and validated for use in this application. The load-pull system's performance is also verified prior to designing the amplifier. A power amplifier is then designed to operate at 3.5 Ghz with an input power of 4mW. (Abstract shortened by UMI.
Demonstration of a passive integrated optics technology based on plasmons.
No full textThe theory surrounding plasmon-polariton wave propagation on infinitely wide thin metal film structures was rederived, understood and is presented. Mode dispersion curves as a function of metal thickness were obtained for various metals and wavelengths. Field distributions for various structures of interest were computed and are presented. Fresnel coefficients have been derived for an n -layer structure to simulate the expected reflectance measurements of attenuated total reflectance (ATR) experiments. ATR experiments have been performed to excite surface plasmon-polaritons on a 20 nm thick titanium (Ti)-gold (Au)-Ti film embedded in SiO2. Measurements of the sensitivity of the thin metal film infinite in width to incident polarisation were performed experimentally confirming the transverse magnetic (TM) nature of surface plasmon-polaritons. A first mask was designed to experimentally verify the optical mode confinement of a thin metal film finite in width. A second mask was designed with the knowledge acquired from the first one. (Abstract shortened by UMI.
Light-opals interaction modeling by direct numerical solution of Maxwell's equations
No full textThis work describes a 3-D Finite-Difference Time-Domain (FDTD) computational approach for the optical characterization of an opal photonic crystal. To fully validate the approach we compare the computed transmittance of a crystal model with the transmittance of an actual crystal sample, as measured over the 400 ÷ 750 nm wavelength range. The opal photonic crystal considered has a face-centered cubic (FCC) lattice structure of spherical particles made of polystyrene (a non-absorptive material with constant relative dielectric permittivity). Light-matter interaction is described by numerically solving Maxwell???s equations via a parallelized FDTD code. Periodic boundary conditions (PBCs) at the outer edges of the crystal are used to effectively enforce an infinite lateral extension of the sample. A method to study the propagating Bloch modes inside the crystal bulk is also proposed, which allows the reconstruction of the ??-k dispersion curve for k sweeping discretely the Brillouin zone of the crystal
- …
