Ultrashort Cross-Correlation In The Middle Infrared: A Novel Approach To Standoff Detection,
2019
University of Nebraska-Lincoln
Ultrashort Cross-Correlation In The Middle Infrared: A Novel Approach To Standoff Detection, William Conner Thomas
Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research
Lasers are a common tool in standoff detection because of their small divergence, large amount of power, and multiple wavelengths available for optical interaction. Optical signatures of targets can be composed of but are not limited to absorption, fluorescence, backscatter, polarization manipulation, and plasma spectra. This work was an investigation of a new signature phenomenon: Dispersion of middle infrared ultrashort laser pulses through gas and vapor phase molecules. Vibrational and rovibrational absorption lines of molecular species affect the spectral phase and spectral amplitude of ultrashort light pulses leading an inititally gaussian temporal profile to become distorted. This dissertation is an …
Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data,
2019
Missouri University of Science and Technology
Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data, Ryan G. Smith, R. Knight
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Land subsidence as a result of groundwater overpumping in the San Joaquin Valley, California, is associated with the loss of groundwater storage and aquifer contamination. Although the physical processes governing land subsidence are well understood, building predictive models of subsidence is challenging because so much subsurface information is required to do so accurately. For the first time, we integrate airborne electromagnetic data, representing the subsurface, with subsidence data, mapped by interferometric synthetic aperture radar (InSAR), to model deformation. By combining both data sets, we are able to solve for hydrologic and geophysical properties of the subsurface to effectively model the …
Fabrication Of Biased-Magnetorheological Elastomers (B-Mre) Based On Magnetized Ferromagnetic Particles,
2019
University of Nevada, Las Vegas
Fabrication Of Biased-Magnetorheological Elastomers (B-Mre) Based On Magnetized Ferromagnetic Particles, Choonghan Lee, Woosoon Yim
Mechanical Engineering Faculty Research
Magnetorheological elastomers (MREs), like MR fluids, exploit magnetic forces between ferromagnetic particles to produce a material with instantaneously adjustable properties of stiffness and damping with external magnetic fields. In MREs, the particles are a part of a structured elastomer matrix, and an external magnetic field is applied to achieve an instantaneous change of stiffness due to magnetic forces between particles. A drawback of conventional MREs is its inability of softening (reduce stiffness) under an external field. Many engineering applications need an instant change of its stiffness in both directions, which requires a magnetic bias embedded in the MRE. One way …
Displacement Damage Effects In Gesn Light Emitting Diodes,
2019
Air Force Institute of Technology
Displacement Damage Effects In Gesn Light Emitting Diodes, Kevin K. Choe
Theses and Dissertations
Potential future use on Earth-orbiting satellites calls for investigation into the suitability of GeSn based photonic devices in high energy proton environments. The electroluminescence (EL) intensity of Ge1-xSnx (x = 0, 0.02, 0.069, and 0.094) light emitting diodes was measured before and after irradiation by 2 MeV protons at relatively high fluence levels. The results showed that GeSn devices with higher Sn content were up to 10 times more resistant against proton displacement damage than the pure Ge (x = 0) devices. As Sn concentration increased, the band gap decreased, and V-P hole trap energy level moved further from the …
Designing Liquid Crystal For Optoacoustic Detection,
2019
Air Force Institute of Technology
Designing Liquid Crystal For Optoacoustic Detection, Michael T. Dela Cruz
Theses and Dissertations
This research impacts the development of a cost-saving, on-chip device that can replace a wide range of costly, bulky sensors for commercial and defense applications. In particular, the goals of this work were to design and test a sensor that uses the optical properties of liquid crystal (LC) to detect acoustic waves. This began with developing a method to fine-tune the optical features of the liquid crystal. Statistical analysis of select experimental variables, or factors, lead to ideal settings of those variables when creating the sensor. A two-factor and three-factor experiment were separately conducted and analyzed as a preliminary demonstration …
Electromagnetic Characterization Of Conductor-Backed Media Using Stepped Rectangular Waveguide,
2019
Air Force Institute of Technology
Electromagnetic Characterization Of Conductor-Backed Media Using Stepped Rectangular Waveguide, Avian Y. Hughes
Theses and Dissertations
A new single stepped-iris waveguide technique is used to nondestructively determine the permittivity and permeability of conductor-backed media. This thesis will demonstrate a proof-of-concept that obtains two independent reflection measurements with a magnetic radar absorbing material (magRAM). Using a two measurement procedure, in which, the first measurement will apply a single rectangular waveguide to a known conductor-backed absorbing material under test (MUT) and the second measurement will insert a stepped-iris in between the single rectangular waveguide and MUT reducing the aperture to retrieve two independent electromagnetic properties (i.e. permittivity and permeability). The theoretical reflection coefficients are obtained using a rigorous …
Ballistic Evaluation Of Carbon Nanotube Sheet Material In Multifunctional Applications,
2019
Air Force Institute of Technology
Ballistic Evaluation Of Carbon Nanotube Sheet Material In Multifunctional Applications, Casey M. Keilbarth
Theses and Dissertations
Significant development of carbon nanotubes has occurred since they were first studied in the 1990's. Attempts to capture the phenomenal molecular properties in practical applications are gaining ground as new methods of producing CNTs have been developed. This thesis sought to determine if the addition of commercially produced CNT sheets to thin carbon fiber panels improved the ballistic properties of the panel. The difference between 0 and 4 CNT sheets was studied. The hypothesis was that inte- grating CNT sheets into the laminate would increase the projectile energy absorbed by the panel and reduce the damage to the panel incurred …
Development Of A Set Of Pre-Class Videos For Electromagnetic Theory,
2019
Anderson University - Indiana
Development Of A Set Of Pre-Class Videos For Electromagnetic Theory, Benjamin Mcpheron, Josiah D. Kunz
ASEE IL-IN Section Conference
One important aspect of experiential learning is allowing students time to reflect on new concepts before the application of the material. Most commonly, this is attempted by assigning readings from a textbook, but research suggests that few students complete these readings. This discouraging fact has prompted the use of other resources, such as videos, to supplement pre-class readings in order to introduce new material. Previous work has been completed by this author to produce pre-class videos for use in an introductory circuits course. This paper extends that work to the development of pre-class videos for a senior level electrical engineering …
Low-Loss, Compact, Spot-Size-Converter Based Vertical Couplers For Photonic Integrated Circuits,
2019
Centre for Advanced Photonics & Process Analysis, Cork Institute of Technology, Cork, Ireland; Tyndall National Institute, Cork, Ireland
Low-Loss, Compact, Spot-Size-Converter Based Vertical Couplers For Photonic Integrated Circuits, Praveen K.J. Singaravelu, G.C.R. Devarapu, Sebastian A. Schulz, Quentin Wilmart, Stéphane Malhouitre, Ségolène Olivier, Liam O’Faolain
Cappa Publications
In recent years, the monolithic integration of new materials such as SiN, Ge and LiNbO3 on silicon (Si) has become important to the Si photonics community due to the possibility of combining the advantages of both material systems. However, efficient coupling between the two different layers is challenging. In this work, we present a spot size converter based on a two-tier taper structure to couple the optical mode adiabatically between Si and SiN. The fabricated devices show a coupling loss as low as 0.058 dB ± 0.01 dB per transition at 1525 nm. The low coupling loss between the Si …
A State-Of-The-Art Survey On Deep Learning Theory And Architectures,
2019
University of Dayton
A State-Of-The-Art Survey On Deep Learning Theory And Architectures, Md Zahangir Alom, Tarek M. Taha, Christopher Yakopcic, Stefan Westberg, Paheding Sidike, Mst Shamima Nasrin, Mahmudul Hasan, Brian C. Van Essen, Abdul A. S. Awwal, Vijayan K. Asari
Electrical and Computer Engineering Faculty Publications
In recent years, deep learning has garnered tremendous success in a variety of application domains. This new field of machine learning has been growing rapidly and has been applied to most traditional application domains, as well as some new areas that present more opportunities. Different methods have been proposed based on different categories of learning, including supervised, semi-supervised, and un-supervised learning. Experimental results show state-of-the-art performance using deep learning when compared to traditional machine learning approaches in the fields of image processing, computer vision, speech recognition, machine translation, art, medical imaging, medical information processing, robotics and control, bioinformatics, natural language …
Experimental Optical Pulse Picker For Lawrence Livermore National Lab,
2019
California Polytechnic State University, San Luis Obispo
Experimental Optical Pulse Picker For Lawrence Livermore National Lab, Alexander Thomas Wargo
Master's Theses
Proprietary.
Optical And Electron Paramagnetic Resonance Characterization Of Point Defects In Semiconductors,
2019
Air Force Institute of Technology
Optical And Electron Paramagnetic Resonance Characterization Of Point Defects In Semiconductors, Elizabeth M. Scherrer
Theses and Dissertations
Point defects in two semiconductor materials, both with promising optical properties, are investigated. The first material, CdSiP2, is a nonlinear optical material in which absorption bands due to point defects can hinder performance when used in frequency conversion applications in the infrared. The second material, Sn2P2S6, is a photorefractive material where point defects with specific properties are needed to optimize response in dynamic holography applications. Electron paramagnetic resonance (EPR) spectroscopy is used to identify the electronic structure of defects and their charge states. Correlations between EPR spectra and optical absorption allow assignments …
A Focal Plane Array And Electronics Model For Cmos And Ccd Sensors In The Afit Sensor And Scene Emulation Tool (Asset),
2019
Air Force Institute of Technology
A Focal Plane Array And Electronics Model For Cmos And Ccd Sensors In The Afit Sensor And Scene Emulation Tool (Asset), Fernando D. Fernandez
Theses and Dissertations
Electro-optical and infrared (EO/IR) sensor models are useful tools that can facilitate understanding a system's behavior without expensive and time-consuming testing of an actual system. EO/IR models are especially important to the military industry where truth data is required but is sometimes impractical to obtain through experimentation due to expense or difficulties in procuring hardware. This work describes implementation of a focal plane array (FPA) model of charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) photodetectors as a component in the Air Force Institute of Technology (AFIT) Sensor and Scene Emulation Tool (ASSET). The FPA model covers conversion of photo-generated …
Design And Implementation Of A 72 & 84 Ghz Terrestrial Propagation Experiment; Exploitation Of Nexrad Data To Statistically Estimate Rain Attenuation At 72 Ghz,
2019
University of New Mexico
Design And Implementation Of A 72 & 84 Ghz Terrestrial Propagation Experiment; Exploitation Of Nexrad Data To Statistically Estimate Rain Attenuation At 72 Ghz, Nicholas Pawel Tarasenko
Electrical and Computer Engineering ETDs
The wireless communication sector is rapidly approaching network capacities as a direct result of increasing mobile broadband data demands. In response, the Federal Communications Commission allocated 71-76 GHz “V-band” and 81-86 GHz “W-band” for terrestrial and satellite broadcasting services. Movement by the telecommunication industry towards W/V-band operations is encumbered by a lack of validated and verified propagation models, specifically models to predict attenuation due to rain. Additionally, there is insufficient data available at W/V-bands to develop or test propagation models. The first aim of this study was the successful installation and operation of a terrestrial link to collect propagation data …
A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things,
2019
Purdue University
A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak
Computer Information Technology Faculty Publications
The realization of Internet of Underground Things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1-0.4m), change in soil moisture impacts …
Electrochromic Semiconductors As Colorimetric Sers Substrates With High Reproducibility And Renewability,
2019
Chinese Academy of Sciences
Electrochromic Semiconductors As Colorimetric Sers Substrates With High Reproducibility And Renewability, Shan Cong, Zhen Wang, Wenbin Gong, Zhigang Chen, Weibang Lu, John R. Lombardi, Zhigang Zhao
Publications and Research
Electrochromic technology has been actively researched for displays, adjustable mirrors, smart windows, and other cutting-edge applications. However, it has never been proposed to overcome the critical problems in the field of surface-enhanced Raman scattering (SERS). Herein, we demonstrate a generic electrochromic strategy for ensuring the reproducibility and renewability of SERS substrates, which are both scientifically and technically important due to the great need for quantitative analysis, standardized production and low cost in SERS. This color-changing strategy is based on a unique quantitative relationship between the SERS signal amplification and the coloration degree within a certain range, in which the SERS …
Mid-Infrared Optical Sensing Using Sub-Wavelength Gratings,
2019
Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork, Ireland and Tyndall National Institute, University College Cork, Cork, Ireland
Mid-Infrared Optical Sensing Using Sub-Wavelength Gratings, Brian Hogan, Liam Lewis, Michael Mcauliffe, Stephen P. Hegarty
Cappa Publications
Optical sensing has shown great potential for both quantitative and qualitative analysis of compounds. In particular sensors which are capable of detecting changes in refractive index at a surface as well as in bulk material have received much attention. Much of the recent research has focused on developing technologies that enable such sensors to be deployed in an integrated photonic device. In this work we demonstrate experimentally, using a sub-wavelength grating the detection of ethanol in aqueous solution by interrogating its large absorption band at 9.54 µm. Theoretical investigation of the operating principle of our grating sensor shows that in …
Parametric Models For Signature Prediction And Feature Extraction,
2019
Air Force Institute of Technology
Parametric Models For Signature Prediction And Feature Extraction, Julie Ann Jackson
Faculty Publications
This paper compares and contrasts numerical electromagnetic (EM) prediction methods and parametric scattering models for radar signature prediction and feature extraction.
Theoretical Analysis Of A Volume Holographic Lens Using Matlab,
2019
Technological University Dublin
Theoretical Analysis Of A Volume Holographic Lens Using Matlab, Sanjay Keshri, Kevin Murphy, Izabela Naydenova, Suzanne Martin
Conference Papers
Volume holographic lenses have great potential for different types of applications requiring light redirection and beam shaping such as solar light collection and LED light management. For lighting applications using LEDs, it is essential to make a highly efficient optical element to be placed in front of the LED in order to decrease energy losses. For that reason, a careful theoretical analysis of the properties and operation regime of the lens must be carried out at the design stage. The characteristics of focusing Holographic Optical Elements (HOE) depend on many factors including their thickness, spatial frequency, the angular range of …
2x-Thru, 1x-Reflection, And Thru-Line De-Embedding: Theory, Sensitivity Analysis, And Error Corrections,
2019
Missouri University of Science and Technology
2x-Thru, 1x-Reflection, And Thru-Line De-Embedding: Theory, Sensitivity Analysis, And Error Corrections, Bichen Chen
Doctoral Dissertations
"Due to the simplicity of design and measurement, as well as the accuracy of results, the 2X-Thru de-embedding (2XTD), 1X-Reflection de-embedding (1XRD), and Thru-Line de-embedding (TLD) have been replaced the traditional de-embedding algorithms, such as TRL and SOLT. In this dissertation, theory of 2n-port 2XTD, 1XRD, and TLD are completely derived first. The self-error reduction schemes is introduced to mitigate the de-embedding errors due to non-ideal manufacturing effects of non-zero mode conversion terms, as well as the asymmetric, and manufacturing variations. The validations are performed on both theory and self-error reduction through simulation and measurements cases. The 2X-Thru …
