Open Access. Powered by Scholars. Published by Universities.®

Electromagnetics and Photonics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 301 - 330 of 1749

Full-Text Articles in Electromagnetics and Photonics

Novel Compact Mimo Antenna Array Structures For 5g, Wi-Fi 6 And Vehicular Applications, Sulaiman Tariq May 2022

Novel Compact Mimo Antenna Array Structures For 5g, Wi-Fi 6 And Vehicular Applications, Sulaiman Tariq

Theses and Dissertations

Due to the fast development of wireless communication applications, the study of Multiple Input Multiple Output (MIMO) communication systems has lately gained comprehensive research interests since it can significantly increase the channel capacity and link reliability without sacrificing bandwidth and/or power transmitted. However, the user equipment is constantly shrinking in size to support more applications and satisfy aesthetic needs, which increases the need for more compact, high-performance antenna array designs. Many techniques are being constantly developed to combat the effects of mutual coupling that arise with the miniaturization of MIMO arrays. This dissertation focuses on designing, testing, and evaluating new …

Go to article

Sub-Nyquist Optical Pulse Sampling For Photonic Blind Source Separation, Taichu Shi, Yang Qi, Weipeng Zhang, Paul Prucnal, Jie Li, Ben Wu May 2022

Sub-Nyquist Optical Pulse Sampling For Photonic Blind Source Separation, Taichu Shi, Yang Qi, Weipeng Zhang, Paul Prucnal, Jie Li, Ben Wu

Henry M. Rowan College of Engineering Departmental Research

We propose and experimentally demonstrate an optical pulse sampling method for photonic blind source separation. The photonic system processes and separates wideband signals based on the statistical information of the mixed signals, and thus the sampling frequency can be orders of magnitude lower than the bandwidth of the signals. The ultra-fast optical pulses collect samples of the signals at very low sampling rates, and each sample is short enough to maintain the statistical properties of the signals. The low sampling frequency reduces the workloads of the analog to digital conversion and digital signal processing systems. In the meantime, the short …

Go to article

Design Of An Offner-Chrisp Imaging Spectrometer For A Planetary Fluorescence Instrument, Tristan Wells Carlson May 2022

Design Of An Offner-Chrisp Imaging Spectrometer For A Planetary Fluorescence Instrument, Tristan Wells Carlson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Spectrometers have been an integral part of space exploration in the late 20th and 21st centuries and will continue to provide quantitative measurements to answer exciting questions like, “Is or was there life on other planets?” PERISCOPE, Probe for Exploring Regolith and Ice by Subsurface Classification of Organics, Polycyclic aromatic hydrocarbons, and Elements, is a next generation spectrometer designed to explore icy worlds like Europa. It uses time-resolved ultraviolet (UV) fluorescence spectroscopy, a technique that identifies organic molecules, polycyclic aromatic hydrocarbons (PAH), and rare earth elements (REE). Photon wavelength discrimination is very important for this technique and is accomplished by …

Go to article

Mutual Coupling Reduction Techniques For Multi-Band Base Station Antennas, Evan Christopher Wayton May 2022

Mutual Coupling Reduction Techniques For Multi-Band Base Station Antennas, Evan Christopher Wayton

Dissertations - ALL

This dissertation proposes antenna design techniques which suppress mutual coupling in densely populated dual-polarized broadband multi-band base station antenna (BSA) arrays for improved radiation characteristics. Array face densification without the proposed techniques leads to undesirable interactions between arrays and radome cover. This research is supported by extensive full-wave electromagnetic simulations, characteristic mode analysis, equivalent circuit models, and array theory. The results are validated through measurements of the radiation patterns and scattering parameters of fabricated prototypes.Upon excitation of a mid-band (MB) array, an electrically long low-band (LB) parasitic, necessary for broadband matching of the baseline LB dipole, exhibits dipole-like induced currents …

Go to article

Analysis And Implementation Of Low Fidelity Radar-Based Remote Sensing For Unmanned Aircraft Systems, Matthew Duck May 2022

Analysis And Implementation Of Low Fidelity Radar-Based Remote Sensing For Unmanned Aircraft Systems, Matthew Duck

Theses and Dissertations

Radar-based remote sensing is consistently growing, and new technologies and subsequent techniques for characterization are changing the feasibility of understanding the environment. The emergence of easily accessible unmanned aircraft system (UAS) has broadened the scope of possibilities for efficiently surveying the world. The continued development of low-cost sensing systems has greatly increased the accessibility to characterize physical phenomena. In this thesis, we explore the viability and implementation of using UAS as a means of radar-based remote sensing for ground penetrating radar (GPR) and polarimetric scatterometry. Additionally, in this thesis, we investigate the capabilities and implementations of low-cost microwave technologies for …

Go to article

Measuring The Electrical Properties Of 3d Printed Plastics In The W-Band, Noah Gregory May 2022

Measuring The Electrical Properties Of 3d Printed Plastics In The W-Band, Noah Gregory

Electrical Engineering Undergraduate Honors Theses

3D printers are a method of additive manufacturing that consists of layering material to produce a 3D structure. There are many types of 3D printers as well as many types of materials that are capable of being printed with. The most cost-effective and well documented method of 3D printing is called Fused Deposition Modeling (FDM). FDM printers work by feeding a thin strand of plastic filament through a heated extruder nozzle. This plastic is then deposited on a flat, typically heated, surface called a print bed. The part is then built by depositing thin layers of plastic in the shape …

Go to article

Electromagnetic Modeling Of A Wind Tunnel Magnetic Suspension And Balance System, Desiree Driver May 2022

Electromagnetic Modeling Of A Wind Tunnel Magnetic Suspension And Balance System, Desiree Driver

Mechanical & Aerospace Engineering Theses & Dissertations

Wind tunnels are used to study forces and moments acting on an aerodynamic body. While most results involve some interference from the mechanical supports used to hold the model, a Magnetic Suspension and Balance System (MSBS) is void of these interferences and presents an ideal test scenario. To further investigate the feasibility of dynamic stability testing at supersonic speeds using a MSBS, a preliminary design idea is currently being developed using an existing MSBS in a subsonic wind tunnel. This review focuses on the development of a mathematical model to more accurately portray the capabilities of the 6 inch Massachusetts …

Go to article

Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar May 2022

Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar

All Dissertations

This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …

Go to article

Diffusive Dynamics Of Biological Macromolecules In The Cytoplasm Of Live Bacteria, Asmaa Sadoon May 2022

Diffusive Dynamics Of Biological Macromolecules In The Cytoplasm Of Live Bacteria, Asmaa Sadoon

Graduate Theses and Dissertations

Bacteria are small organisms that play important roles in our bodies and in maintaining our surrounding environment. However, bacterial infections are considered as one of the health diseases that threatens the lives of humans. Resistance of bacteria to antibiotics has made treating bacterial infections more challenging. With the emergence of many developed optical techniques, it has become possible to study various biological mechanisms of molecules inside these small organisms with high resolution and precise localization. In this research, single particle tracking photoactivation localization microscopy (sptPALM) technique was used to investigate the dynamics of fluorescent histonelike nucleoid-structuring proteins (H-NS) in live …

Go to article

Understanding The Radiation Effects On Fiber Optic Sensors, Sohel Rana May 2022

Understanding The Radiation Effects On Fiber Optic Sensors, Sohel Rana

Boise State University Theses and Dissertations

In this dissertation, the effects of radiation (gamma, neutron or mixed gamma and neutron) on optical fiber sensors are studied and new techniques for real-time measurement of radiation-induced macroscopic changes in optical fibers are presented. It is crucial among the research and development efforts in the nuclear energy field to conduct experiments in Advanced Test Reactor (ATR) to support lifetime extension, novel fuels and materials development, better fuel management, and enhanced safety of existing as well as future nuclear power plants (NPP). Due to their unparalleled and unique advantages over traditional sensors, optical fiber sensors are deemed potential candidates for …

Go to article

Second-Order Enhanced Coupling Strength Grating Out-Couplers For A Monolithic Laser-Electro-Absorption Modulator, Maryam Dezfuli Apr 2022

Second-Order Enhanced Coupling Strength Grating Out-Couplers For A Monolithic Laser-Electro-Absorption Modulator, Maryam Dezfuli

Electrical Engineering Theses and Dissertations

Conventional grating out-couplers in III-V waveguides typically require lengths of several hundreds of microns to outcouple 50 to 90% of the incident optical power. Enhanced coupling strength (ECS) gratings, which reduce the out-coupler grating length to tens of microns, have a large relative permittivity difference between the materials on either side of the grating boundary along with a high index cover layer. With appropriately chosen permittivity and layer thicknesses, the addition of a cover layer “pulls” the peak of the optical mode towards the grating region, resulting in a significant increase in the grating confinement factor. The resulting ECS out-coupler …

Go to article

Microscopic Nuclei Classification, Segmentation, And Detection With Improved Deep Convolutional Neural Networks (Dcnn), Md Zahangir Alom, Vijayan K. Asari, Anil Parwani, Tarek M. Taha Apr 2022

Microscopic Nuclei Classification, Segmentation, And Detection With Improved Deep Convolutional Neural Networks (Dcnn), Md Zahangir Alom, Vijayan K. Asari, Anil Parwani, Tarek M. Taha

Electrical and Computer Engineering Faculty Publications

Background Nuclei classification, segmentation, and detection from pathological images are challenging tasks due to cellular heterogeneity in the Whole Slide Images (WSI). Methods In this work, we propose advanced DCNN models for nuclei classification, segmentation, and detection tasks. The Densely Connected Neural Network (DCNN) and Densely Connected Recurrent Convolutional Network (DCRN) models are applied for the nuclei classification tasks. The Recurrent Residual U-Net (R2U-Net) and the R2UNet-based regression model named the University of Dayton Net (UD-Net) are applied for nuclei segmentation and detection tasks respectively. The experiments are conducted on publicly available datasets, including Routine Colon Cancer (RCC) classification and …

Go to article

An Investigation Into Magnetic Gears And Magnetic Springs For Marine Hydrokinetic Power Generators, Hossein Baninajar Apr 2022

An Investigation Into Magnetic Gears And Magnetic Springs For Marine Hydrokinetic Power Generators, Hossein Baninajar

Dissertations and Theses

Marine hydrokinetic generators often use mechanical gears to convert the low-speed motion into the high-speed rotary motion that is required for conventional electrical generators. While mechanical gearboxes have a high torque density and can reach high efficiencies, they suffer from serious reliability issues. Recently, magnetic gearing technology has been proposed as a means of making hydrokinetic generators more reliable. As magnetic gears use magnetic field modulation to create speed change, they offer a high reliability, nonfriction, power transmission mechanism that limits the wear to only the bearings and makes the magnetic gears almost maintenance-free. During an over-torque condition, a magnetic …

Go to article

Towards Improved Inertial Navigation By Reducing Errors Using Deep Learning Methodology, Hua Chen, Tarek M. Taha, Vamsy P. Chodavarapu Apr 2022

Towards Improved Inertial Navigation By Reducing Errors Using Deep Learning Methodology, Hua Chen, Tarek M. Taha, Vamsy P. Chodavarapu

Electrical and Computer Engineering Faculty Publications

Autonomous vehicles make use of an Inertial Navigation System (INS) as part of vehicular sensor fusion in many situations including GPS-denied environments such as dense urban places, multi-level parking structures, and areas with thick tree-coverage. The INS unit incorporates an Inertial Measurement Unit (IMU) to process the linear acceleration and angular velocity data to obtain orientation, position, and velocity information using mechanization equations. In this work, we describe a novel deep-learning-based methodology, using Convolutional Neural Networks (CNN), to reduce errors from MEMS IMU sensors. We develop a CNN-based approach that can learn from the responses of a particular inertial sensor …

Go to article

Pseudo-Modal Expansions For Generating Random Electromagnetic Beams, Milo W. Hyde Iv, Olga Korotkova Apr 2022

Pseudo-Modal Expansions For Generating Random Electromagnetic Beams, Milo W. Hyde Iv, Olga Korotkova

Faculty Publications

Excerpt: We derive two pseudo-modal expansions that provide insight into the structure of stationary electromagnetic sources and can be used for their physical realization and in computer simulations. Both expansions are derived from the vectorial version of Bochner’s theorem of functional analysis.

Go to article

Aerial Radiation Detection Identification And Measurement System Detector Material Comparison Study, Benjamin C. Troxell, Kacey D. Mcgee, Christina L. Dugan Apr 2022

Aerial Radiation Detection Identification And Measurement System Detector Material Comparison Study, Benjamin C. Troxell, Kacey D. Mcgee, Christina L. Dugan

Faculty Publications

The 20th Chemical Biological Radiological Nuclear and Explosives Command (CBRNE) currently utilizes an airborne sodium iodide gamma and beta detection system to map radiation fields over large areas of interest. The 20th CBRNE explored emergent detector technologies utilizing two detection materials; thallium-activated cesium iodide and high purity germanium (HPGe). These detectors were simulated at various altitudes and compared to background measurements. The sodium iodide detector failed to provide isotopic discrimination at distance. The thallium-activated cesium iodide CsI(Tl) detector provided sufficient absolute efficiency and energy resolution to identify isotopics at distance. The HPGe detector provided the best energy resolution. However, current …

Go to article

Polarization-Sensitive Optical Responses From Natural Layered Hydrated Sodium Sulfosalt Gerstleyite, Ravi P. N. Tripathi, Xiaodong Yang, Jie Gao Mar 2022

Polarization-Sensitive Optical Responses From Natural Layered Hydrated Sodium Sulfosalt Gerstleyite, Ravi P. N. Tripathi, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-element layered materials have gained substantial attention in the context of achieving the customized light-matter interactions at subwavelength scale via stoichiometric engineering, which is crucial for the realization of miniaturized polarization-sensitive optoelectronic and nanophotonic devices. Herein, naturally occurring hydrated sodium sulfosalt gerstleyite is introduced as one new multi-element van der Waals (vdW) layered material. The mechanically exfoliated thin gerstleyite flakes are demonstrated to exhibit polarization-sensitive anisotropic linear and nonlinear optical responses including angle-resolved Raman scattering, anomalous wavelength-dependent linear dichroism transition, birefringence effect, and polarization-dependent third-harmonic generation (THG). Furthermore, the third-order nonlinear susceptibility of gerstleyite crystal is estimated by the probed …

Go to article

Magnetic Flux Channel Antenna Design In Conformal Applications, William J. Tremblay Mar 2022

Magnetic Flux Channel Antenna Design In Conformal Applications, William J. Tremblay

Theses and Dissertations

Magnetic Flux Channels (MFC) and Magneto-Dielectric Wire Antennas (MDWA) are effective, and in some cases, superior alternatives to traditional metallic antennas, in conformal and electrically small applications at the cost of fabrication and feed complexity. The frequency dispersive nature of magnetic material constituent parameters imposes constraints on the antenna design process, which were not fully developed in prior art. This research quantifies the key differences between the operating regions of magneto-dielectric materials for antenna applications and demonstrates the effectiveness of numerical method augmented modal analysis in the design process, regardless of operating region. Modeling challenges associated with MDWAs are addressed …

Go to article

Magnetic Anomaly Absolute Positioning For Hypersonic Aircraft, Alexander J. Mcneil Mar 2022

Magnetic Anomaly Absolute Positioning For Hypersonic Aircraft, Alexander J. Mcneil

Theses and Dissertations

GPS has proven to be an extremely valuable asset for navigation, and timing. GPS has become the standard navigation system for all applications, but GPS has limitations. GPS is susceptible to jamming, spoofing, and in the case of hypersonic aircraft, is likely unavailable. When an aircraft is traveling at hypersonic speeds, there is a plasma sheath that surrounds the aircraft. This plasma sheath blocks electromagnetic waves, and is therefore responsible for a GPS blackout. GPS unavailability for hypersonic aircraft has prompted the research into the viability of alternate navigation systems for these aircraft. This paper seeks to explore the viability …

Go to article

Malware Detection Using Electromagnetic Side-Channel Analysis, Matthew A. Bergstedt Mar 2022

Malware Detection Using Electromagnetic Side-Channel Analysis, Matthew A. Bergstedt

Theses and Dissertations

Many physical systems control or monitor important applications without the capacity to monitor for malware using on-device resources. Thus, it becomes valuable to explore malware detection methods for these systems utilizing external or off-device resources. This research investigates the viability of employing EM SCA to determine whether a performed operation is normal or malicious. A Raspberry Pi 3 was set up as a simulated motor controller with code paths for a normal or malicious operation. While the normal path only calculated the motor speed before updating the motor, the malicious path added a line of code to modify the calculated …

Go to article

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew Jan 2022

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

We report a radially and azimuthally polarized (raPol) microscope for high detection and estimation performance in single-molecule orientation-localization microscopy (SMOLM). With 5000 photons detected from Nile red (NR) transiently bound within supported lipid bilayers (SLBs), raPol SMOLM achieves 2.9 nm localization precision, 1.5° orientation precision, and 0.17 sr precision in estimating rotational wobble. Within DPPC SLBs, SMOLM imaging reveals the existence of randomly oriented binding pockets that prevent NR from freely exploring all orientations. Treating the SLBs with cholesterol-loaded methyl-β-cyclodextrin (MβCD-chol) causes NR’s orientational diffusion to be dramatically reduced, but curiously NR’s median lateral displacements drastically increase from 20.8 to …

Go to article

Characteristic Mode Analysis Prediction And Guidance Of Electromagnetic Coupling Measurements To A Uav Model, Mohamed Z. M. Hamdalla, Benjamin Bissen, James D. Hunter, Yuanzhuo Liu, Victor Khilkevich, Daryl G. Beetner, Anthony N. Caruso, Ahmed M. Hassan Jan 2022

Characteristic Mode Analysis Prediction And Guidance Of Electromagnetic Coupling Measurements To A Uav Model, Mohamed Z. M. Hamdalla, Benjamin Bissen, James D. Hunter, Yuanzhuo Liu, Victor Khilkevich, Daryl G. Beetner, Anthony N. Caruso, Ahmed M. Hassan

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The simplified surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to properties of the incident excitation waveform, such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and …

Go to article

A Deep Neural Network For Early Detection And Prediction Of Chronic Kidney Disease, Vijendra Singh, Vijayan K. Asari, Rajkumar Rajasekaran Jan 2022

A Deep Neural Network For Early Detection And Prediction Of Chronic Kidney Disease, Vijendra Singh, Vijayan K. Asari, Rajkumar Rajasekaran

Electrical and Computer Engineering Faculty Publications

Diabetes and high blood pressure are the primary causes of Chronic Kidney Disease (CKD). Glomerular Filtration Rate (GFR) and kidney damage markers are used by researchers around the world to identify CKD as a condition that leads to reduced renal function over time. A person with CKD has a higher chance of dying young. Doctors face a difficult task in diagnosing the different diseases linked to CKD at an early stage in order to prevent the disease. This research presents a novel deep learning model for the early detection and prediction of CKD. This research objectives to create a deep …

Go to article

Direct Laser Writing Below The Diffraction Limit By Exploring Multi-Pulse-Induced Physics, Boyang Zhou Jan 2022

Direct Laser Writing Below The Diffraction Limit By Exploring Multi-Pulse-Induced Physics, Boyang Zhou

Electronic Theses and Dissertations, 2020-2023

Ultrafast laser ablation has enabled high-precision processing of a wide range of materials including metals, semiconductors, dielectrics, and polymers. Several laser nanostructuring methods exist, including those based on optical near-fields, special material properties, surface plasmons, and multiphoton absorption (MPA). Among these methods, the MPA method has the potential for nanoscale direct laser writing by using a simple experimental setup. However, the understanding of the fundamental mechanism involved in the laser ablation process is still incomplete, and it remains challenging to obtain a feature size much smaller than the diffraction-limited spot size. The goal of this research is to understand how …

Go to article

4.74 Ghz Harmonically Operated Saw Device For Sensing Applications And Interrogation System, Michael Morales Otero Jan 2022

4.74 Ghz Harmonically Operated Saw Device For Sensing Applications And Interrogation System, Michael Morales Otero

Electronic Theses and Dissertations, 2020-2023

Surface acoustic wave (SAW) devices have provided solutions to many sensor applications. With the increasing use of the electromagnetic spectrum, the adoption of higher frequencies for new developments is becoming a necessity. SAW devices represent a solution for advancing many emerging sensor's needs given their inherent advantages such as: wireless operation, low cost, and ease of fabrication. However, the SAW technology has been typically limited to frequencies under 3 GHz due to size limitations, increased SAW losses, and the need of an interrogation system suitable for reading SAW sensors at higher frequencies. This dissertation presents the work done to push …

Go to article

Numerical Investigations Of 2-D Magnetic Nozzles On Pulsed Plasma Plumes, Joshua Daniel Burch Jan 2022

Numerical Investigations Of 2-D Magnetic Nozzles On Pulsed Plasma Plumes, Joshua Daniel Burch

Masters Theses

"This research presents studies of a novel type of magnetic nozzle that allows for three-dimensional (3-D) steering of a plasma plume. Numerical simulations were performed using Tech-X's USim® software to quantify the nozzle's capabilities. A2-D planar magnetic nozzle was applied to plumes of a nominal pulsed inductive plasma (PIP) source with discharge parameters similar to those of Missouri S&T's Missouri Plasmoid Experiment (MPX). Argon and xenon plumes were considered. Simulations were verified and validated through a mesh convergence study as well as comparison with available experimental data. Periodicity was achieved over the simulation run time and phase angle samples were …

Go to article

A Progressive Learning Strategy For Large-Scale Glacier Mapping, Zhiyuan Xie, Umesh K. Haritashya, Vijayan K. Asari Jan 2022

A Progressive Learning Strategy For Large-Scale Glacier Mapping, Zhiyuan Xie, Umesh K. Haritashya, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

In recent years, the worldwide temperature increase has resulted in rapid deglaciation and a higher risk of glacier-related natural hazards such as flooding and debris flow. Due to the severity of these hazards, continuous observation and detailed analysis of glacier fluctuations are crucial. Many such analyses require an accurately delineated glacier boundary. However, the complexity and heterogeneity of glaciers, particularly debris-covered glaciers (DCGs), poses a challenge for glacier mapping when using conventional remote sensing or machine-learning techniques. Some examples exist about small-scale automated glacier mapping, but large or regional-scale mapping is challenging. Previously, a deep-learning-based approach named GlacierNet2 had been …

Go to article

Volumetric Microfabrication With Structured Light, He Cheng Jan 2022

Volumetric Microfabrication With Structured Light, He Cheng

Electronic Theses and Dissertations, 2020-2023

Multiphoton polymerization (MPP) as one of the direct laser writing techniques is capable of manufacturing three-dimensional (3D) micro-structures with complex shapes and novel functionalities. However, current MPP methods rely on point-by-point or layer-by-layer scanning and therefore are time-consuming. The low fabrication throughput of conventional MPP is the key factor that limits its wider adoption for industrial manufacturing over large surface area. One way to increase the fabrication speed is to turn layer-by-layer process into a volumetric process. An ideal volumetric printing method can fabricate structures with complex 3D geometry by single exposure and should be easy to implement. As a …

Go to article

Patterned Liquid Crystal Devices For Near-Eye Displays, Kun Yin Jan 2022

Patterned Liquid Crystal Devices For Near-Eye Displays, Kun Yin

Electronic Theses and Dissertations, 2020-2023

As a promising next-generation display, augmented reality (AR) and virtual reality (VR) have shown attractive features and attracted broad interests from both academia and industry. Currently, these near-eye displays (NEDs) have enabled numerous applications, ranging from education, medical, entertainment, to engineering, with the help of compact and functional patterned liquid crystal (LC) devices. The interplay between LC patterns and NEDs stimulates the development of novel LC devices with unique surface alignments and volume structures, which in turn feedback to achieve more compact and versatile NEDs. This dissertation will focus on the patterned LC with applications in NEDs. Firstly, we propose …

Go to article

Light Guiding And Concentrating Using Self-Collimating Spatially-Variant Photonic Crystals, Chun Xia Jan 2022

Light Guiding And Concentrating Using Self-Collimating Spatially-Variant Photonic Crystals, Chun Xia

Electronic Theses and Dissertations, 2020-2023

Advances in integrated photonic devices require low loss, easy-to-integrate solutions for chip-to-chip and chip-to-fiber interfacing. Among the most common solutions are traditional lenses. However, circular lenses require additional mounting mechanisms to ensure proper alignment. Additionally, the beam routing functionality cannot be added to the traditional lenses unless they are combined with mirrors and operate in the reflection mode. In this dissertation, we investigate lens-embedded photonic crystals (LEPCs) as a solution to flat and multifunctional lenses. The concept is demonstrated by creating self-collimating lattices containing a gradient refractive index lens (GRIN-LEPC), a binary-shaped lens (B-LEPC), and a Fresnel-type binary-shaped lens (F-B-LEPC). …

Go to article

First Prev Next Last