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Articles 1 - 13 of 13
Full-Text Articles in Physics
Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver, Robert Beattie-Rossberg
Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver, Robert Beattie-Rossberg
Electrical and Computer Engineering ETDs
A twelve-brick air insulated linear transformer driver (LTD) was characterized by charging to voltages ranging from 30 to 70 kV and delivering energy to two separate resistive loads. Various plasma diagnostics were built and fielded with an emphasis on the design, implementation and analysis of a Mach Zehnder interferometer, a moiré deflectometer and a spectroscopy system providing information on the temporal evolution of plasma electron density and atomic composition. Rogowski coils, XRD radiation detectors, framing camera images and time integrated DSLR images are used to further understand load conditions where current data, x ray radiation data, velocity data and instability …
Intracavity Phase Interferometry Based Fiber Sensors, Luke Jameson Horstman
Intracavity Phase Interferometry Based Fiber Sensors, Luke Jameson Horstman
Optical Science and Engineering ETDs
Intracavity Phase Interferometry (IPI) is a detection technique that exploits the inherent sensitivity of a laser's frequency to the parameters of its cavity. Intracavity interferometry is orders of magnitude more sensitive than its extracavity alternatives. This dissertation improves on previous free-space proof-of-concept designs. By implementing the technique in fiber optics, using optical parametric oscillation, and investigating non-Hermitian quantum mechanics and dispersion tailoring enhancement techniques, IPI has become more applicable and sensitive. Ring and linear IPI configurations were realized in this work, both operating as bidirectional fiber optical parametric oscillators. The benefit of using externally pumped synchronous optical parametric oscillation is …
Heterogeneously Integrated Photonic Modulators And High-Volume Manufacturing Of Related Technologies, Nicholas Adam Boynton
Heterogeneously Integrated Photonic Modulators And High-Volume Manufacturing Of Related Technologies, Nicholas Adam Boynton
Electrical and Computer Engineering ETDs
Silicon photonics is an attractive approach to cost-effective integrated optics due to the infrastructure established for silicon CMOS electronics. The material properties of silicon however are not ideal for optical devices. Specifically, silicon lacks the ability to easily produce light-emitting devices due to its indirect bandgap, and has a centro-symmetric crystal structure which does not facilitate the Pockels effect required for linear modulation. Conversely, lithium niobate is an excellent optical material due to its strong Pockels effect but, is a notoriously difficult material to process. One method of simultaneously overcoming the material limitations of silicon and the fabrication limitations of …
On The Dynamic Generation Of Megagauss-Level Magnetic Fields On 100-Ns Timescales To Stabilize And Magnetize Pulsed-Power-Driven Liner Implosions, Gabriel A. Shipley
On The Dynamic Generation Of Megagauss-Level Magnetic Fields On 100-Ns Timescales To Stabilize And Magnetize Pulsed-Power-Driven Liner Implosions, Gabriel A. Shipley
Electrical and Computer Engineering ETDs
This dissertation presents analysis of experiments and simulations executed to develop the auto-magnetizing liner concept (AutoMag) for use as an alternative premagnetization mechanism for MagLIF. Tests of each stage of AutoMag (magnetization, dielectric breakdown, and implosion) were executed on the Mykonos accelerator and the Z accelerator. Experiments demonstrate strong peak axial magnetic field production (20 – 150 T), dielectric breakdown initiation that depends on global induced electric field across the target, and a level of cylindrical implosion uniformity high enough to be useful for prospective fusion-fuel-filled (auto-magnetized MagLIF) experiments.
This dissertation also presents detailed simulations of the Solid Liner Dynamic …
Integrated Chirped-Grating Spectrometer-On-A-Chip, Shima Nezhadbadeh
Integrated Chirped-Grating Spectrometer-On-A-Chip, Shima Nezhadbadeh
Optical Science and Engineering ETDs
In this dissertation we demonstrate a new structure based on waveguide coupling atop a silicon wafer using a chirped grating to provide the dispersion that leads to a high-resolution, compact, fully integrable and CMOS-compatible spectrometer. Light is both analyzed and detected in a single, completely monolithic component which enables realizing a high-resolution portable spectrometer with an extremely compact footprint. The structure is comprised of a SiO2/Si3N4/SiO2 waveguide on top of a silicon wafer. Grating regions are fabricated on the top cladding of the waveguide. The input light is incident on a chirped grating …
Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia
Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia
Electrical and Computer Engineering ETDs
A metamaterial (MTM) high power microwave (HPM) vacuum electron device (VED) was developed using 3D printing technology. The specific geometric pattern of the source can produce both negative permittivity and permeability to interact with a relativistic electron beam. The electron beam is generated using a pulsed electron accelerator with a maximum energy of 700 keV and lasting approximately 16 ns. The design of this novel VED consists of a circular waveguide loaded with complementary split-ring resonators in a linear periodic arrangement in which the relativistic beam travels guided by a magnetic field. The electrons interact with the MTM producing electromagnetic …
Symmetry And Dopant Diffusion In Inverted Nanopyramid Arrays For Thin Crystalline Silicon Solar Cells, Seok Jun Han
Symmetry And Dopant Diffusion In Inverted Nanopyramid Arrays For Thin Crystalline Silicon Solar Cells, Seok Jun Han
Chemical and Biological Engineering ETDs
In this dissertation, we enhance the efficiency of thin flexible monocrystalline silicon solar cells by breaking symmetry in light trapping nanostructures and improving homogeneity in dopant concentration profile. These thin cells are potentially less expensive than conventional thick silicon cells by using less silicon material and making the cells more convenient to be handled when supported on polymer films. Moreover, these cells are widely applicable due to their flexibility and lightweight. However, for high efficiencies, these cells require effective light trapping and charge collection. We achieve these in cells based on 14-mm-thick free-standing silicon films with light-trapping arrays of nanopyramidal …
Novel Compact Narrow-Linewidth Mid-Infrared Lasers For Sensing Applications, Behsan Behzadi
Novel Compact Narrow-Linewidth Mid-Infrared Lasers For Sensing Applications, Behsan Behzadi
Optical Science and Engineering ETDs
The mid-infrared (2-14 μm) spectral region contains the strong absorption lines of many important molecular species, which make this region crucial for several well-know applications such as spectroscopy, chemical and biochemical sensing, security, and industrial monitoring. To fully exploit this region through absorption spectroscopic techniques, compact and low-cost narrow-linewidth (NLW) mid-infrared (MIR) laser sources are of primary importance.
This thesis is focused on three novel compact NLW MIR lasers: demonstration and characterization of a new glass-based spherical microlaser, investigation of the performance of a novel fiber laser, and the design of a monolithic laser on a silicon chip. Starting with …
An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter
An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter
Nuclear Engineering ETDs
Modern ultraviolet (UV) cameras, when combined with UV-transmitting lenses/filter arrangements, can be used to detect radiation dose in air. Ionizing radiation excites nitrogen molecules in ambient air, the resulting decay includes weak emission of ultraviolet photons. Previous work has proven this phenomenon is detectable using highly-sensitive electronically cooled cameras traditionally used in astronomy for low-background imaging. While the ability to detect the presence of radiation (i.e. qualitative measurement) has been demonstrated at Sandia National Laboratories, there are several challenges in correlating images to known dose-fields (quantitative measurement). These challenges include: a low signal to background ratio, interferences due to electronic …
Nanowire-Based Light-Emitting Diodes: A New Path Towards High-Speed Visible Light Communication, Mohsen Nami
Nanowire-Based Light-Emitting Diodes: A New Path Towards High-Speed Visible Light Communication, Mohsen Nami
Physics & Astronomy ETDs
Nano-scale optoelectronic devices have gained significant attention in recent years. Among these devices are semiconductor nanowires, whose dimeters range from 100 to 200 nm. Semiconductor nanowires can be utilized in many different applications including light-emitting diodes and laser diodes. Higher surface to volume ratio makes nanowire-based structures potential candidates for the next generation of photodetectors, sensors, and solar cells. Core-shell light-emitting diodes based on selective-area growth of gallium nitride (GaN) nanowires provide a wide range of advantages. Among these advantages are access to non-polar m-plane sidewalls, higher active region area compared to conventional planar structures, and reduction of threading …
Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu
Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu
Optical Science and Engineering ETDs
Metrology technologies are an essential adjunct to Integrated Circuit (I.C.) Semiconductor manufacturing. Scatterometry, an optical metrology, was chosen to measure 50 nm half pitch feature structures. A bread-board scatterometry system has been assembled to provide a non-contact, non-destructive, accurate and flexible measurement. A real-time, on-line scatterometry system has also been demonstrated and proven to provide a high throughput measurement.
Three different types of samples have been measured using the scatterometry setup. The wire-grid polarizer (WGP) sample has been made by Jet and Flash Nanoimprint Lithography with ~100 nm pitch and ~50 nm wide ~200 nm tall Al gratings on fused …
Experimental Investigation Of Plasma Dynamics In Jets And Bubbles Using A Compact Coaxial Plasma Gun In A Background Magnetized Plasma, Yue Zhang
Electrical and Computer Engineering ETDs
Numerous solar and astrophysical observations of jet- and bubble-like plasma structures exhibit morphological similarities, suggesting that there may be common plasma physics at work in the formation and evolution processes of these structures at different system scales. The ideal magnetohydrodynamics (MHD) provide the necessary theoretical basis for employing laboratory experiments to investigate key physical processes in nonlinear astrophysical and solar systems, especially when magnetic fields are present.
A coaxial magnetized plasma gun has been designed, installed, and operated in the HelCat linear device at the University of New Mexico. In Region I, a current-driven plasma jet is formed. The plasma …
Transistorized Circuits For Telemetry, Dominick Misciascio Jr.
Transistorized Circuits For Telemetry, Dominick Misciascio Jr.
Physics & Astronomy ETDs
This thesis is concerned with the telemetry of small DC signals from photomultiplier tubes. The circuitry must have a high input impedance so as not to load down the photomultiplier tube and a low output impedance which is capable of controlling the current through a small incandescent bulb. This bulb is used to illuminate a photoresistor. The output of the circuit consists of a variation of the resistance of the photoresistor. This variable resistance is conventionally converted into a variable audio frequency which is transmitted to the receiving station on a radio-frequency carrier. The output resistance must be independent of …