Compact And High Optical Efficiency Near-Eye Displays With Liquid Crystal Flat Optics,
2023
University of Central Florida
Compact And High Optical Efficiency Near-Eye Displays With Liquid Crystal Flat Optics, Junyu Zou
Electronic Theses and Dissertations, 2020-2023
Since the concepts of augmented reality (AR) and virtual reality (VR) were introduced, they have attracted people's attention worldwide, both in the industry and research areas. As the most promising hardware architecture that can bring AR/VR into daily life, near eye displays (NEDs) have been studied and investigated heavily over the past half-century, especially the concept of "Metaverse" introduced by some top companies in recent years. However, the form factor and optical efficiency are two major bottlenecks for the current NEDs before they can become the major platform. Liquid crystal (LC) flat optics have several advantages, including compact, high diffraction …
Emission Spectroscopy Of Ingaas Quantum Dots Via High-Resolution Fabry-Perot Interferometer,
2023
West Virginia University
Emission Spectroscopy Of Ingaas Quantum Dots Via High-Resolution Fabry-Perot Interferometer, Raju Bhai Kc
Graduate Theses, Dissertations, and Problem Reports (ETD)
Single photons emitted from self-assembled quantum dots have been widely studied to use as a promising qubit for quantum information processing. Therefore, it is critical to fully understand the emission spectra from the quantum dot's excitation if we want to use a single photon as a quantum bit. It is almost impossible to produce rotationally symmetric quantum dots due to various growth conditions and restrictions. So the real quantum dots do not have a perfectly symmetric structure. A broken rotational symmetry causes an asymmetric exchange interaction between electron and hole, leading to a fine structure splitting between two excited states. …
Concept Connectivity: An Educational And Research Framework For Scientific Learning In Optics, Photonics, And Electronic Education,
2023
Ateneo de Manila University
Concept Connectivity: An Educational And Research Framework For Scientific Learning In Optics, Photonics, And Electronic Education, Benjamin Dingel, John Gabriel C. Rivera, Francesca De Guzman Palabrica, Clint Dominic Bennett
Physics Faculty Publications
We present a novel framework referred to as Concept Connectivity that aids in educating and engaging students by presenting the topic of the Special Theory of Relativity (STR) in a coherent and unified manner. It uses different analogue implementations of the STR coming from seemingly distinct fields of study such as (i) Optics, (ii) Photonics, and (iii) Electronics to connect not only to the concepts of the STR but to the various concepts from these different fields. In these analogue implementations, the fundamental characteristics of the different STR phenomena can be mimicked in many different ways. Concept Connectivity has two …
Design And Fabrication Of Volume Holographic Optical Couplers For A Range Of Non-Normal Incidence Angles,
2023
Technological University Dublin, Ireland
Design And Fabrication Of Volume Holographic Optical Couplers For A Range Of Non-Normal Incidence Angles, Dipanjan Chakraborty, Rosen Georgiev, Sinead Aspell, Izabela Naydenova, Suzanne Martin
Conference Papers
A theoretical model has previously been developed to calculate the holographic recording beam angles required in air (at any recording wavelength) to produce a Volume Holographic Optical Element (VHOE) for operation as a coupler for different input and output angles. In this paper, the experimental study is extended to further validate the VHOE coupler design and fabrication approach for additional incident beam angles, comparing -40° -45° and -50° (in air). The output angle for each VHOE is +45° within the medium and the coupler operational wavelength is 633nm. Holographic recording in Bayfol HX 200 photopolymer at 532nm is used to …
Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries,
2023
Technological University of the Shannon, Ireland
Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries, Andrea Bourke, Daniela Oboroceanu, Nathan Quill, Catherine Lenihan, Maria Alhajji Safi Maria Alhajji Safi, Mallory A. Miller, Robert F. Savinell, Jesse S. Wainright, Varsha Sasikumarsp, Maria Rybalchenko, Pupak Amini, Niall Dalton, Robert P. Lynch, D. Noel Buckley
Articles
Two aspects of vanadium flow batteries are reviewed: electrochemical kinetics on carbon electrodes and positive electrolyte stability. There is poor agreement between reported values of kinetic parameters; however, most authors report that kinetic rates are faster for VIV/VV than for VII/VIII. Cycling the electrode potential increases the rates of both reactions initially due to roughening but when no further roughening is observed, the VII/VIII and VIV/VV reactions are affected oppositely by the pretreatment potential. Anodic pretreatment activates the electrode for the VII/VIII reaction, and deactivates it for VIV/VV. Three states of the carbon surface are suggested: reduced and oxidized states …
Color-Changing Reflection Hologram For Quality Assurance Of Therapeutic Ultrasound Systems,
2023
Technological University Dublin
Color-Changing Reflection Hologram For Quality Assurance Of Therapeutic Ultrasound Systems, Tatsiana Mikulchyk, John Walsh, Jacinta Browne, Izabela Naydenova, Dervil Cody
Articles
The acoustic output of clinical therapeutic ultrasound equipment requires regular quality assurance (QA) testing to ensure the safety and efficacy of the treatment and that any potentially harmful deviations from the expected output power density are detected as soon as possible. A hologram, consisting of a reflection grating fabricated in an acrylate photopolymer film, has been developed to produce an immediate, visible, and permanent change in the color of the reconstructed hologram from red to green in response to incident ultrasound energy. The influence of the therapeutic ultrasound insonation parameters (exposure time, ultrasound power density, and proximity to the point …
The Development Of Optomechanical Sensors—Integrating Diffractive Optical Structures For Enhanced Sensitivity,
2023
Technological University Dublin
The Development Of Optomechanical Sensors—Integrating Diffractive Optical Structures For Enhanced Sensitivity, Faolan Radford Mcgovern, Aleksandra Hernik, Catherine M. Grogan, George Amarandei, Izabela Naydenova
Conference Papers
The term optomechanical sensors describes devices based on coupling the optical and mechanical sensing principles. The presence of a target analyte leads to a mechanical change, which, in turn, determines an alteration in the light propagation. Having higher sensitivity in comparison with the individual technologies upon which they are based, the optomechanical devices are used in biosensing, humidity, temperature, and gases detection. This perspective focuses on a particular class, namely on devices based on diffractive optical structures (DOS). Many configurations have been developed, including cantilever- and MEMS-type devices, fiber Bragg grating sensors, and cavity optomechanical sensing devices. These state-of-the-art sensors …
The Employees’ Perspective: Situational Leadership Style Flexibility And Effectiveness And Employee Performance In A Technological Organization,
2023
Walden University
The Employees’ Perspective: Situational Leadership Style Flexibility And Effectiveness And Employee Performance In A Technological Organization, Merari Cortes
Walden Dissertations and Doctoral Studies
Poor employee performance can have adverse effects on business outcomes. Business leaders are concerned with poor performance, which can minimize profitability and negatively impact business sustainability. Grounded in the Situational Leadership II® model, the purpose of this quantitative correlational study was to examine the relationship between situational leadership style flexibility, effectiveness, and employee performance as perceived by employees, controlling for employee gender, job location, and tenure. A random sample of 99 technology company employees completed the Leader Behavior Analysis II®– Other and the Employee Job Performance measurement tools. Using hierarchical multilinear regression, employee gender, job location, and tenure were entered …
Surface Reconstruction In Iron Garnets,
2023
Michigan Technological University
Surface Reconstruction In Iron Garnets, Sushree Dash
Dissertations, Master's Theses and Master's Reports
This dissertation presents the results of a study investigating the physical mechanisms underlying an unexpectedly large increase in magneto-optic efficiency observed in iron garnet. Such materials are technologically important for telecommunications due to their nonreciprocal optical action. In the past, our group had found evidence of an enhanced Faraday rotation in bismuth-substituted iron garnet films less than 50 nm thick. Subsequent investigation revealed that this enhancement could be traced to surface effects. This is significant because understanding these phenomena could be used to formulate engineering solutions for device miniaturization. In this dissertation, we present the result of a research project …
Optical Phase Transition Characteristics In Germanium-Antimony-Selenium-Tellurium And Graphene Oxide Thin Film For Application In Photonics Memory.,
2023
Universiti Malaya
Optical Phase Transition Characteristics In Germanium-Antimony-Selenium-Tellurium And Graphene Oxide Thin Film For Application In Photonics Memory., Gan Soon Xin
Student Works (2020-2029)
This thesis aims to study the phase change characteristic of Ge2Sb2Se4Te1 (GSST) using 1550 nm pulsed laser as excitation source, and to explore its potential in multilevel nonvolatile photonic memory application. Firstly, the amorphous to crystalline state phase transition of GSST using 1550 nm pulsed laser as optical excitation source is investigated. The threshold laser pulse duration to achieve crystallization are 190 ns, 140 ns, 100 ns and 70 ns for laser intensities of 0.46 GW/cm2, 0.61 GW/cm2, 0.76 GW/cm2 and 0.85 GW/cm2, respectively. However, it is found that the phase change tolerance of GSST is very stringent (phase transition …
The Behavior Of Partially Coherent Twisted Space-Time Beams In Atmospheric Turbulence,
2023
Air Force Institute of Technology
The Behavior Of Partially Coherent Twisted Space-Time Beams In Atmospheric Turbulence, Milo W. Hyde Iv
Faculty Publications
We study how atmospheric turbulence affects twisted space-time beams, which are non-stationary random optical fields whose space and time dimensions are coupled with a stochastic twist. Applying the extended Huygens–Fresnel principle, we derive the mutual coherence function of a twisted space-time beam after propagating a distance z through atmospheric turbulence of arbitrary strength. We specialize the result to derive the ensemble-averaged irradiance and discuss how turbulence affects the beam’s spatial size, pulse width, and space-time twist. Lastly, we generate, in simulation, twisted space-time beam field realizations and propagate them through atmospheric phase screens to validate our analysis.
Fabrication And Optical Properties Of Two-Dimensional Transition Metal Dichalcogenides,
2023
Michigan Technological University
Fabrication And Optical Properties Of Two-Dimensional Transition Metal Dichalcogenides, Manpreet Boora
Dissertations, Master's Theses and Master's Reports
Two-dimensional layered materials such as graphene and transition metal dichalcogenides have gained a lot of attention because of their distinctive chemical, optical, and electronic properties. Transition metal dichalcogenides can have a tunable bandgap in the range of 1 − 3 eV (visible), which enables their applications in ultrathin field effect transistors, photovoltaics, sensors, and optoelectronic devices. They exhibit an indirect-to-direct band gap transition when thinned down from bulk to a single layer. They show strong photoluminescence, electron–photon interaction, valley pseudospin, nonlinear optical response, and lack of dangling bonds. Many exotic phenomena appear when materials are thinned to nanoscale size because …
Photonic Monitoring Of Atmospheric Fauna,
2022
New Jersey Institute of Technology
Photonic Monitoring Of Atmospheric Fauna, Adrien P. Genoud
Dissertations
Insects play a quintessential role in the Earth’s ecosystems and their recent decline in abundance and diversity is alarming. Monitoring their population is paramount to understand the causes of their decline, as well as to guide and evaluate the efficiency of conservation policies. Monitoring populations of flying insects is generally done using physical traps, but this method requires long and expensive laboratory analysis where each insect must be identified by qualified personnel. Lack of reliable data on insect populations is now considered a significant issue in the field of entomology, often referred to as a “data crisis” in the field. …
Atom-Specific Probing Of Electron Dynamics In An Atomic Adsorbate By Time-Resolved X-Ray Spectroscopy,
2022
Stockholm University
Atom-Specific Probing Of Electron Dynamics In An Atomic Adsorbate By Time-Resolved X-Ray Spectroscopy, Simon Schreck, Elias Diesen, Martina Dell'angela, Chang Liu, Matthew Weston, Flavio Capotondi, Hirohito Ogasawara, Jerry Larue, Roberto Costantini, Martin Beye, Piter S. Miedema, Joakim Halldin Stenlid, Jörgen Gladh, Boyang Liu, Hsin-Yi Wang, Fivos Perakis, Filippo Cavalca, Sergey Koroidov, Peter Amann, Emanuele Pedersoli, Denys Naumenko, Ivaylo Nikolov, Lorenzo Raimondi, Frank Abild-Pedersen, Tony F. Heinz, Johannes Voss, Alan C. Luntz, Anders Nilsson
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The electronic excitation occurring on adsorbates at ultrafast timescales from optical lasers that initiate surface chemical reactions is still an open question. Here, we report the ultrafast temporal evolution of x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) of a simple well-known adsorbate prototype system, namely carbon (C) atoms adsorbed on a nickel [Ni(100)] surface, following intense laser optical pumping at 400 nm. We observe ultrafast (∼100 fs) changes in both XAS and XES showing clear signatures of the formation of a hot electron-hole pair distribution on the adsorbate. This is followed by slower changes on a few picoseconds …
Temperature Influence On The Optical Properties, Attenuation Coefficient, And Total Molecular Cross Section Of Dhunge Dhara Drinking Water,
2022
Department of Physics, Patan Multiple Campus, Tribhuvan University, Lalitpur 44700, Nepal
Temperature Influence On The Optical Properties, Attenuation Coefficient, And Total Molecular Cross Section Of Dhunge Dhara Drinking Water, Saddam Husain Dhobi, Bibek Koirala, Kishori Yadav, Jeevan Jyoti Nakarmi, Suresh Prasad Gupta, Santosh Kumar Das, Arun Kumar Shah, Kuldip Paudel, Kushal Dahal, Ram Lal Sah
Makara Journal of Science
This work aims to measure the different parameters of Dhunge Dhara water (DDW) such as absorbance, transmittance, mass attenuation coefficient (MAC), and molecular cross section (MCS) and experimentally compare the obtained values with those of pure water (PW) at various temperatures (5 °C to 90 °C) using a theremino spectrometer. Observation shows that the parameters vary with temperature and wavelength. The transmittance of DDW ranges from 18% to 85% and absorbance of the same ranges from 0.09 Au to 0.7 Au. Meanwhile, the transmittance of PW ranges from 40% to 98% and the absorbance of the same ranges from 0.09 …
Multi-Plane Light Conversion: Devices And Applications,
2022
University of Central Florida
Multi-Plane Light Conversion: Devices And Applications, Yuanhang Zhang
Electronic Theses and Dissertations, 2020-2023
Multi-plane light conversion (MPLC) has recently been developed as a versatile tool for manipulating spatial distributions of the optical field through repeated phase modulations. An MPLC Device consists of a series of phase masks separated by free-space propagation. It can convert one orthogonal set of beams into another orthogonal set through unitary transformation, which is useful for a number of applications. In telecommunication, for example, mode-division multiplexing (MDM) is a promising technology that will enable continued scaling of capacity by employing spatial modes of a single fiber. MPLC has shown great potential in MDM devices with ultra-wide bandwidth, low insertion …
Temporal Optical Activity And Chiral Time-Interfaces [Invited],
2022
CUNY Advanced Science Research Center
Temporal Optical Activity And Chiral Time-Interfaces [Invited], Shixiong Yin, Yao-Ting Wang, Andrea Alù
Advanced Science Research Center
Time-interfaces, at which the optical properties of a medium undergo abrupt and spatially uniform changes, have attracted surging interest in optics and wave physics. In this work, we study wave scattering at time-interfaces involving chiral media. Dual to spatial interfaces involving chiral media, we show that a propagating wave is split upon a chiral time-interface into two orthogonal circular polarization waves oscillating at different frequencies. We formulate the temporal scattering boundary-value problem at such time-interfaces, and then demonstrate the effect of temporal optical activity through a chiral time-slab. The effect of material dispersion is also analyzed, highlighting interesting opportunities in …
Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy,
2022
Mississippi State University
Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen
Theses and Dissertations
The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …
Six-Dimensional Single-Molecule Imaging With Isotropic Resolution Using A Multi-View Reflector Microscope,
2022
Washington University in St. Louis
Six-Dimensional Single-Molecule Imaging With Isotropic Resolution Using A Multi-View Reflector Microscope, Oumeng Zhang, Zijian Guo, Yuanyuan He, Tingting Wu, Michael D. Vahey, Matthew D. Lew
Electrical & Systems Engineering Publications and Presentations
Imaging of both the positions and orientations of single fluorophores, termed single-molecule orientation-localization microscopy, is a powerful tool for the study of biochemical processes. However, the limited photon budget associated with single-molecule fluorescence makes high-dimensional imaging with isotropic, nanoscale spatial resolution a formidable challenge. Here we realize a radially and azimuthally polarized multi-view reflector (raMVR) microscope for the imaging of the three-dimensional (3D) positions and 3D orientations of single molecules, with precisions of 10.9 nm and 2.0° over a 1.5-μm depth range. The raMVR microscope achieves 6D super-resolution imaging of Nile red molecules transiently bound to lipid-coated spheres, accurately resolving …
Supercontinuum Light Generation Via Non-Linear Effects In Hollow-Core Fiber,
2022
University of Arkansas, Fayetteville
Supercontinuum Light Generation Via Non-Linear Effects In Hollow-Core Fiber, Skyler Gulati
Physics Student Works
The field of non-linear optics has gained traction in the last couple decades due to the variable generation of wavelengths which are less deterministic than within traditional optics. Using non-linear mediums, including hollow-core fibers (HCF), generation of wavelengths spanning into the vacuum ultraviolet (VUV) wavelength range is possible. These short wavelengths can be utilized within electron spectroscopy-based methods of material science like angle-resolved photoemission spectroscopy (ARPES). This technique most often uses specific photoemission lines of atoms in discharge lamps, however, with the frequency dispersion capabilities of HCF, broad band creation can allow for variable wavelength selection through filtering specific wavelengths …
