Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 54 for “"field enhancement"”.
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Nonlinear optical emission and near-field enhancement effects in arrays of gold bowtie nano-antennas
… investigates the effects of the large near-field intensity enhancements from periodic arrays of gold bowtie nano-antennas (BNAs) after illumination by laser light. Specifically, we focus on laser-induced damage, nonlinear optical emission, and a proof-of-concept for utilizing arrays of gold …
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Study of Field Enhancement by Spherical Voids in Gold Lattices by Using Three Dimensional Finite Difference Time Domain Simulations
… increase in the intensity of the light (field enhancement) near the metal surface. Field enhancement properties of nanostructured metals can significantly enhance efficiency of an upconverter used in solar cells. The objective of this work was to develop an understanding why selfassembled …
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An analytical framework for field electron emission, incorporating quantum- confinement effects
As field electron emitters shrink to nanoscale dimensions, the effects of quantum confinement of the electron supply and electric field enhancement at the emitter tip play a significant role in determining the emitted current density (ECD). Consequently, the Fowler-Nordheim (FN) equation, which …
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Nanoscale Control of Gap-plasmon Enhanced Optical Processes
… years. The strong plasmon-mediated electric field enhancement and field confinement well beyond the diffraction limit has been demonstrated to improve the performance of optical devices including ultrasensitive sensors, light emitters, and optical absorbers. A plasmon resonance mode of …
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Flat optics based on patterned nanostructures for concentrating light
… in these structures leads to both a large field enhancement and thermal response. We found that intrinsic absorption in the pBNAs leads to significant heating, the result of which could promote optically guided delamination of the metal from its dielectric pillar. We showed that this …
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Electrical characterization of EEPROM test structures
… to the data must take into account the area and field enhancement dependencies. The curve fits allow for variations in tunneling area, field enhancement, and current density to be used as metrics for comparison of device lifetimes. Noise measurements were done to attempt to correlate tunneling …
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Optical Properties of Individual Nano-Sized Gold Particle Pairs
… single MNPs, which both affect the local optical fields in their vicinity: the distance between them, and their relative orientation with respect to the polarisation of the excitation light. These properties are subject of three chapters: One section examines the distance-dependent and …
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Pillar-supported plasmonic nanoantennas for optical nanotweezers and optical audio applications
… momentum transfer from confined electromagnetic fields within micro- and nanoscale objects to form non-invasive probes that serve to provide piconewton forces and detect motion with angstrom-level precision. This technique was discovered in the 1980s and has been found useful in a variety of …
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The Self-Assembly, Optical Response and Stretch Tunability of Plasmonic Nanoparticle Monolayers
… Additionally, the manipulation of near-field enhancement between particles via the application of strain increases the degree of enhancement observed in surface enhanced Raman spectroscopy. By manipulating forces such as interfacial tension and by tuning the electrostatic repulsion …
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Engineered Plasmonic Nanostructures for Infrared Spectroscopy, Refractive Index Sensing and Nonlinear Optics
… sensing applications. The intense and localized field, generated by two adjacent metallic nanostructures when appropriately illuminated, has been utilized for enhancing the sensitivity of vibrational spectroscopy. The near-field enhancement is also responsible for benefiting device properties, …
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Optical Metamaterials: Design, Characterization and Applications
… I have extended subdiffraction imaging to far-field at infrared wavelengths. Utilizing a two-dimensional array of silver nanorods that provides near-field enhancement, I numerically show that subwavelength features can be resolved in far-field in the form of Moire features. Development of this …
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Integrated plasmonic nano-antenna devices
… lasers can generate high-intensity electric fields inside the nano-antennas; for example, the use of a parabolic taper can yield an electric field enhancement of 7 (for a 50 nm air gap). Alternatively, slot waveguides are proposed for coupling light into nano-antennas without significant …
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Cavity Plasmonics - Exploring narrow-gap plasmonic coupled systems to boost, localize and exploit nanometric light -matter interaction
… in the NPoM configuration. Due to their large field enhancement reaching values of the order of 10^4 and mode volumes as small as 40 nm^3 they form a versatile sensing platform. A custom-built polarization dark-field microscope is used to probe the morphology of the NPoM cavities on …
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The Effects Of Electrode Geometry On Current Pulse Caused By Electrical Discharge Over An Ultra-fast Laser Filament
… electron collisional ionization brought about by field enhancement at the tips. Additional discrepancies in the currents measured leaving the high-voltage electrode and that returning to ground were also observed. Implications for potential laser-induced discharge applications will be discussed.
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Field emission from carbon nanotubes deposited on platinum and nickel/nickel oxide multilayers
… carbon nanotubes have been shown to be excellent field emitters, very little is known about the emission mechanism. This work strives to gain insight on field enhancement in films of single-walled carbon nanotubes by studying the internal field emission between the back contact metal and the …
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Enhanced Rainbow Trapping in Width-graded Chirped MIM Nano-gratings for High-sensitivity Multiwavelength Bio-molecular Detection
… mode transformation are satisfied. Maximal field enhancement is attained by ensuring adiabatic mode transformation among the grooves through parametric optimization of groove width and groove-to-groove separation. Experimentally, we fabricate nano-gratings using electron beam lithography …
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Fabrication and characterisation of silver-glass nanocomposites
… Metallic nanostructures show local field enhancement effects, which are used for example in surface enhanced Raman scattering. Their large surface area compared to bulk materials makes them interesting for applications in chemistry and life science.<br/>In this thesis the synthesis …
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Tailored Optical Properties on the Macroscale by Template-Assisted Self-Assembly of Plasmonic Nanoparticles
… part focuses on the efficient and homogeneous field-enhancement of close-packed assemblies of gold nanoparticles that serve as platforms for surface-enhanced Raman scattering (SERS) spectroscopy.
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Large area plasmonic nanostructures design, fabrication and characterization by laser
… nanostructures. The intense electromagnetic fields by free electron oscillations at the metal surface provide promising applications, of which plasmonic sensing is a prime example. However, the development of practical, low-cost nanoscale manufacturing tools and processes capable of realizing …
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Field emission of ZnO nano-structures produced by laser ablation
… deposition of ZnO materials for applications as field electron emission sources. The results from the work are concerned with the study of the important physical processes present in a laser ablation zinc oxide plasma plume expanding into vacuum and various ambient gas pressures. The thesis also …
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