Optics Commons^™

Spectroscopic End Point Detection With An Electron Beam Evaporator, Ryan Mcgraw

University Honors Theses

Spectroscopic end point detection is a common tool used for measuring slope changes in wavelength intensity. Using algorithms able to apply this concept, coatings will be able to be dynamically measured in real time and stopped at the appropriate level to ensure process uniformity. It is currently applied to reductive processes such as etching, where the surface will start to be eaten away, creating a plasma. When the entire amount of a material on a substrate has been eaten away, the plasma will change color as it is beginning to etch a different material. Using a spectrometer, this point where …

Applications Of Independent And Identically Distributed (Iid) Random Processes In Polarimetry And Climatology, Dan Kestner

Dissertations, Master's Theses and Master's Reports

The unifying theme of this thesis is the characterization of “perfect randomness,” i.e., independent and identically distributed (IID) stochastic processes as these are applied in physical science. Two specific and mathematically distinct applications are chosen: (i) Radar and optical polarimetry; (ii) Analysis of time series in meteorology. In (i), IID process of a special kind, namely, with a distribution defined by symmetry, is used to link its multivariate Gaussian density to uniformity on the Poincaré sphere. This “statistical ellipsometry” approach is then used to relate polarimetric mismatches or imbalances to ellipsometric variables and suitably chosen cross-correlation measures. In (ii), recently …

Acoustically Levitated Whispering-Gallery Mode Microlasers, H. M. Reynoso-De La Cruz, E. D. Hernández-Campos, E. Ortiz-Ricardo, A. Martínez-Borquez, I. Rosas-Román, V. Contreras, G. Ramos-Ortiz, B. Mendoza-Santoyo, Cecilia Zurita-Lopez, R. Castro-Beltrán

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Acoustic levitation has become a crucial technique for contactless manipulation in several fields, particularly in biological applications. However, its application in the photonics field remains largely unexplored. In this study, we implement an affordable and innovative phased-array levitator that enables stable trapping in the air of micrometer dye-doped droplets, thereby enabling the creation of microlasers. For the first time, this paper presents a detailed performance of the levitated microlaser cavity, supported by theoretical analysis concerning the hybrid technology based on the combination of whispering-gallery modes and acoustic fields. The pressure field distribution inside the acoustic cavity is numerically solved and …

Entanglement In The Hawking Effect: From Astrophysical To Optical Black Holes, Dimitrios Kranas

LSU Doctoral Dissertations

The Hawking effect is an exciting physical prediction lying at the intersection of the two most successful theories of the past century, namely, Einstein’s theory of relativity and quantum mechanics. In this dissertation, we put special emphasis on the quantum aspects of the Hawking process encoded in the entanglement shared by the emitted fluxes of created quanta. In particular, we employ sharp tools from quantum information theory to quantify the entanglement produced by the Hawking effect throughout the black hole evaporation process. Our framework allows us to extend previous calculations of entanglement to a larger set of cases, for instance, …

Adaptive Plasmonic Metasurfaces For Radiative Cooling And Passive Thermoregulation, Azadeh Didari-Bader, Nooshin M. Estakhri, Nasim Mohammadi Estrakhri

Engineering Faculty Articles and Research

In this work, we investigate a class of planar photonic structures operating as passive thermoregulators. The radiative cooling process is adjusted through the incorporation of a phase change material (Vanadium Dioxide, VO₂) in conjunction with a layer of transparent conductive oxide (Aluminum-doped Zinc Oxide, AZO). VO₂ is known to undergo a phase transition from the “dielectric” phase to the “plasmonic” or “metallic” phase at a critical temperature close to 68°C. In addition, AZO shows plasmonic properties at the long-wave infrared spectrum, which, combined with VO₂, provides a rich platform to achieve low reflections across the …

Characterization Of Boreal-Arctic Vegetation Growth Phases And Active Soil Layer Dynamics In The High-Latitudes Of North America: A Study Combining Multi-Year In Situ And Satellite-Based Observations, Michael G. Brown

Dissertations, Theses, and Capstone Projects

This dissertation examined the seasonal freeze/thaw activity in boreal-Arctic soils and vegetation physiology in Alaska, USA and Alberta, Canada, using in situ environmental measurements and passive microwave satellite observations. The boreal-Arctic high-latitudes have been experiencing ecosystem changes more rapidly in comparison to the rest of Earth due to the presently warming climatic conditions having a magnified effect over Polar Regions. Currently, the boreal-Arctic is a carbon sink; however, recent studies indicate a shift over the next century to become a carbon source. High-latitude vegetation and cold soil dynamics are influenced by climatic shifts and are largely responsible for the regions …

Modeling Uv Light Through N95 Filters, Lorenzo Hess

Honors Projects

Reuse of N95 FFRs helps mitigate the effects of shortages. UV-C exposure is an ideal method for the decontamination necessary for FFR reuse. Recent research quantifies the transmittance of UV-C through the 3M1870+ and 3M9210+ FFRs [1]. Other research measures the reduction in viral load in relation to UV-C exposure time [11]. We design and program a ray tracing simulator in MATLAB to characterize the distribution of scattered photons in N95 FFRs. We implement an object-oriented FFR with configurable physical characteristics. We use the simulator to record the number of photons available for decontamination in each sub-layer of the filtering …

Electro-Optical Sensors For Atmospheric Turbulence Strength Characterization With Embedded Edge Ai Processing Of Scintillation Patterns, Ernst Polnau, Don L. N. Hettiarachchi, Mikhail A. Vorontsov

Electro-Optics and Photonics Faculty Publications

This study introduces electro-optical (EO) sensors (TurbNet sensors) that utilize a remote laser beacon (either coherent or incoherent) and an optical receiver with CCD camera and embedded edge AI computer (Jetson Xavier Nx) for in situ evaluation of the path-averaged atmospheric turbulence refractive index structure parameter C-n(2) at a high temporal rate. Evaluation of C-n(2) values was performed using deep neural network (DNN)-based real-time processing of short-exposure laser-beacon light intensity scintillation patterns (images) captured by a TurbNet sensor optical receiver. Several pre-trained DNN models were loaded onto the AI computer and used for TurbNet sensor performance evaluation in a set …

Perovskite Solar Cells, Liqiu Zheng Dr., Tyler Hurst, Zhongrui Li

Georgia Journal of Science

The semiconductor perovskite CsPbBr₂I was doped with Mn²⁺ to modulate its optical and photovoltaic performance. The Mn²⁺-doped CsPb_0.9Mn_0.1Br₂I exhibited improved crystalline quality. Ultraviolet and visible spectroscopy of Mn²⁺-doped CsPb_0.9Mn_0.1Br₂I revealed enhanced absorption capacity. Although the efficiency was not as good as desired, the enhanced light absorption of CsPb_0.9Mn_0.1Br₂I still boosted the photovoltaic performance when it was utilized as a light absorber in perovskite solar cells, along with a low-cost carbon electrode. Compared with its counterpart …

Wavelength And Power Dependence On Multilevel Behavior Of Phase Change Materials, Gary A. Sevison, Joshua A. Burrow, Haiyun Guo, Andrew M. Sarangan, Joshua R. Hendrickson, Imad Agha

Electro-Optics and Photonics Faculty Publications

We experimentally probe the multilevel response of GeTe, Ge2Sb2Te5 (GST), and 4% tungsten-doped GST (W-GST) phase change materials (PCMs) using two wavelengths of light: 1550 nm, which is useful for telecom-applications, and near-infrared 780 nm, which is a standard wavelength for many experiments in atomic and molecular physics. We find that the materials behave differently with the excitation at the different wavelengths and identify useful applications for each material and wavelength. We discuss thickness variation in the thin films used as well and comment on the interaction of the interface between the material and the substrate with regard to the …

Optical Switching Performance Of Thermally Oxidized Vanadium Dioxide With An Integrated Thin Film Heater, Andrew M. Sarangan, Gamini Ariyawansa, Ilya Vitebskiy, Igor Anisimov

Electro-Optics and Photonics Faculty Publications

Optical switching performance of vanadium dioxide produced by thermal oxidation of vanadium is presented in this paper. A 100nm thick vanadium was oxidized under controlled conditions in a quartz tube furnace to produce approximately 200nm thick VO2. The substrate was appropriately coated on the front and back side to reduce reflection in the cold state, and an integrated thin film heater was fabricated to allow in-situ thermal cycling. Electrical measurements show a greater than three orders of magnitude change in resistivity during the phase transition. Optical measurements exhibit 70% transparency at 1500nm and about 15dB extinction across a wide spectral …

Assembly And Detection Of 3-D Qr Codes Through Additive Manufacturing And Terahertz Imaging, Patrick Dunn

Theses

Automatic identification and data capture, or AIDC, plays a substantial role in contemporary business, advertising, and military needs. The purpose of this study is to generate a potential alternative to current AIDC approaches by constructing three-dimensional plastic tags (or ‘3D QR codes’) using additive manufacturing techniques and interrogate them using Terahertz radiation. 3D Quick Response (QR) codes are designed in 3D computer-aided design software. The QR codes are 3D structures embedded in the printed plastic in which an air gap in the plastic (or an air gap filled in with another type of plastic) indicates a bit of information. Information …

Plasmon-Driven Nanowire Actuators For On-Chip Manipulation, Shuangyi Linghu, Zhaoqi Gu, Jinsheng Lu, Wei Fang, Zongyin Yang, Huakang Yu, Zhiyuan Li, Runlin Zhu, Jian Peng, Qiwen Zhan, Songlin Zhuang1, Min Gu, Fuxing Gu

Electro-Optics and Photonics Faculty Publications

Chemically synthesized metal nanowires are promising building blocks for next-generation photonic integrated circuits, but technological implementation in monolithic integration will be severely hampered by the lack of controllable and precise manipulation approaches, due to the strong adhesion of nanowires to substrates in non-liquid environments. Here, we demonstrate this obstacle can be removed by our proposed earthworm-like peristaltic crawling motion mechanism, based on the synergistic expansion, friction, and contraction in plasmon-driven metal nanowires in non-liquid environments. The evanescently excited sur- face plasmon greatly enhances the heating effect in metal nanowires, thereby generating surface acoustic waves to drive the nanowires crawling along …

Tunable Optical Filter Using Phase Change Materials For Smart Ir Night Vision Applications, Remona Heenkenda, Keigo Hirakawa, Andrew Sarangan

Electro-Optics and Photonics Faculty Publications

In this paper we present a tunable filter using Ge2Sb2Se4Te1 (GSST) phase change material. The design principle of the filter is based on a metal-insulator-metal (MIM) cavity operating in the reflection mode. This is intended for night vision applications that utilize 850nm as the illumination source. The filter allows us to selectively reject the 850nm band in one state. This is illustrated through several daytime and nighttime imaging applications.

Understanding The Effects Of Water Vapor And Temperature On Aerosol Using Novel Measurement Methods, Tyler Jacob Capek

Dissertations, Master's Theses and Master's Reports

Aerosol and water are inexorably linked, and both are ubiquitous within our atmosphere and required components for cloud formation. Relative humidity (RH), a temperature dependent quantity, can have a significant influence on the size, shape, and ultimately, the optical properties of the aerosol. RH can vary substantially on small spatial and short temporal scales in turbulent conditions due to rapid fluctuations in temperature and water vapor mixing ratio. Accurate assessment of optical enhancements due to an increase in RH is key for determining the particles’ impact on the climate and visibility.

A humidity-controlled cavity attenuated phase-shift albedometer (H-CAPS-PM_SSA) …

Drawing Parallels In Art Science For Collaborative Learning: A Case Study, Karen Westland

The STEAM Journal

This research paper explores drawing as a tool to facilitate interdisciplinary practice. Outlined is the personal experience of PhD researcher [name removed] in their physics/craft research project, combined with thoughts and opinions from collaborators gathered through group discursive interviews. Interdisciplinary projects face interpersonal and conceptually ambiguous challenges which can be addressed through adopting drawing techniques for educational purposes. Findings highlight that drawing can assist across a breadth of applications as a learning tool for everyone, regardless of drawing ability, to improve the functionality of collaborative projects. Specifically, drawing combined with other communication techniques develops a performative communicative approach that enriches …

Polarization-Selective Modulation Of Supercavity Resonances Originating From Bound States In The Continuum, Chan Kyaw, Riad Yahiaoui, Joshua A. Burrow, Viet Tran, Kyron Keelen, Wesley Sims, Eddie C. Red, Willie S. Rockward, Mikkel A. Thomas, Andrew M. Sarangan, Imad Agha, Thomas A. Searles

Electro-Optics and Photonics Faculty Publications

Bound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling …

Atmospheric Turbulence Study With Deep Machine Learning Of Intensity Scintillation Patterns, Artem V. Vorontsov, Mikhail A. Vorontsov, Grigorii A. Fillimonov, Ernst Polnau

Electro-Optics and Photonics Faculty Publications

A new paradigm for machine learning-inspired atmospheric turbulence sensing is developed and applied to predict the atmospheric turbulence refractive index structure parameter using deep neural network (DNN)-based processing of short-exposure laser beam intensity scintillation patterns obtained with both: experimental measurement trials conducted over a 7 km propagation path, and imitation of these trials using wave-optics numerical simulations. The developed DNN model was optimized and evaluated in a set of machine learning experiments. The results obtained demonstrate both good accuracy and high temporal resolution in sensing. The machine learning approach was also employed to challenge the validity of several eminent atmospheric …

Artificial Neural Network Discovery Of A Switchable Metasurface Reflector, J. R. Thompson, J. A. Burrow, P. J. Shah, J. Slagle, E. S. Harper, A. Van Rynbach, I. Agha, M. S. Mills

Electro-Optics and Photonics Faculty Publications

Optical materials engineered to dynamically and selectively manipulate electromag- netic waves are essential to the future of modern optical systems. In this paper, we simulate various metasurface configurations consisting of periodic 1D bars or 2D pillars made of the ternary phase change material Ge2Sb2Te5 (GST). Dynamic switching behavior in reflectance is exploited due to a drastic refractive index change between the crystalline and amorphous states of GST. Selectivity in the reflection and transmission spectra is manipulated by tailoring the geometrical parameters of the metasurface. Due to the immense number of possible metasurface configurations, we train deep neural networks capable of …

Development And Demonstration Of A Pico-Watt Calorimeter For Optical Absorption Spectroscopy, Behshad Roshanzadeh

Optical Science and Engineering ETDs

An optical calorimeter for sensitive absorption measurements of non-radiative samples at 4 K was designed, built, and demonstrated. It consists of a cryostat cooled by a commercial pulse tube (PTC) refrigerator, a measurement chamber housing the sample and thermometers, and various fiber-coupled light sources. By employing measures to damp mechanical noise from the environment and active temperature stabilization of critical components of the instrument temperature noise as low as 6 nK/√Hz at 50 mHz was achieved under 15 mW of optical excitation. An optical absorption induced temperature increase of the sample as small as 2.5 nK could be resolved using …

Overview Of Trends In Indian Optics Research (2008 – 2018), Mallikarjun Kappi, Biradar B S

Library Philosophy and Practice (e-journal)

The present study deals with the assessment of Indian optics research output as reflected in Web of Science (WOS) database for the period 2008 to 2018 for identifying the research output in the field of optics literature. It also provides a comparative evaluation and performance of different types of scientometric indicators, such as number of publications, number of citations and collaboration from India. The Indian optics research has increased exponentially over the last decade.

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …

Stacked Volume Holographic Gratings For Extending The Operational Wavelength Range In Led And Solar Applications, Sanjay Keshri, Julia Marín-Sáez, Izabela Naydenova, Kevin Murphy, Jesús Atencia, Daniel Chemisana, Sean Garner, María-Victoria Collados, Suzanne Martin

Articles

A novel stacking procedure is presented for volume phase holographic gratings (VPHGs) recorded in photopolymer material using Corning Willow Glass as a flexible substrate in order to achieve broader angular and spectral selectivity in a diffractive device with high efficiency for solar and LED applications. For the first time to our knowledge, we have shown a device designed for use with a white LED that has the same input and output angles and high efficiency when illuminated by different wavelengths. In this paper, two VPHGs were designed, experimentally recorded, and tested when illuminated at normal incidence. The experimental approach is …

Electrodynamics Modeling Of Plasmonic-Organic Hybrid Waveguides, Marcus Michel

Pomona Senior Theses

Optical fibers have multiple advantages over conventional electrical connections, such as lower energy losses and higher bandwidth. To use optics for chip-to-chip communication, electro-optic (EO) modulators need to be scaled down to be incorporated on integrated circuits. This size reduction has been accomplished using plasmonic-organic hybrid (POH) waveguides, which make use of nonlinear organic EO materials and surface plasmon polaritons to achieve light modulation in devices with lengths on the micron scale. As these devices are just starting to be developed, there are many avenues for their potential optimization. In order to streamline and reduce the cost of the optimization …

Electromagnetic Analysis Of Bidirectional Reflectance From Roughened Surfaces And Applications To Surface Shape Recovery, Julian Antolin Camarena

Physics & Astronomy ETDs

Scattering from randomly rough surfaces is a well-established sub area of electrodynamics. There remains much to be done since each surface and optical processes that may occur in within the scattering medium, and countless other scenarios, is different. There are also illumination models that describe lighting in a scene on the macroscopic scale where geometrical optics can be considered adequate. Of particular interest for us is the intersection of the physical scattering theories and the illumination models. We present two contributions: 1) A minimum of two independent images are needed since any opaque surface can be uniquely specified in terms …

Rare Event Sampling In Applied Stochastic Dynamical Systems, Yiming Yu

Dissertations

Predicting rare events is a challenging problem in many complex systems arising in physics, chemistry, biology, and materials science. Simulating rare events is often prohibitive in such systems due to their high dimensionality and the numerical cost of their simulation, yet analytical expressions for rare event probabilities are usually not available. This dissertation tackles the problem of approximation of the probability of rare catastrophic events in optical communication systems and spin-torque magnetic nanodevices. With the application of the geometric minimum action method, the probability of pulse position shifts or other parameter changes in a model of an actively mode-locked laser …

Topological Insulating States In Photonics And Acoustics, Xiang Ni

Dissertations, Theses, and Capstone Projects

Recent surge of interest in topological insulators, insulating in their interior but conducting at the surfaces or interfaces of different domains, has led to the discovery of a variety of new topological states, and their topological invariants are characterized by numerous approaches in the category of topological band theory. The common features shared by topological insulators include, the topological phase transition occurs if the bulk bandgap is formed due to the symmetries reduction, the topological invariants exist characterizing the global properties of the material and inherently robust to disorder and continuous perturbations irrespective of the local details. Most importantly, these …

High-Pressure High-Temperature Exploration Of Phase Boundaries Using Raman Spectroscopy, Jasmine Kashmir Hinton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Metastability of states can provide interesting properties that may not be readily accessible in a material’s ground state. Many materials show high levels of polymorphism, indicating a rich energy landscape and a potential for metastable states. Melt crystallization techniques provide a potential route to these states. We use a resistively heated diamond anvil cell (DAC) with fine control of a system’s pressure and temperature to explore these systems. Raman spectroscopy is used to track subtle structural changes across phase boundaries. Organic systems, such as glycine and aspirin, were our initial interest due to their high polymorphism and reported low melting …

The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic

Physics and Astronomy

In this experiment, we used the optical emission spectroscopy (OES) method to obtain the main properties of low temperature Argon plasma. The experiment was sustained in powers and pressures that ranges from 30-100 W and 15-100 mTorr. We used numerical methods for the Argon kinetic model to calculate metastable levels and resonant states for the first excited states in low temperature Argon plasma. By finding the ratio of two spectral lines and finding another ratio from a different upper energy level that goes down to the same two lower energy levels, we can construct a system of two nonlinear equations. …

Scattering Of Few Photon Fields By Two Level Systems In A One Dimensional Geometry, William Konyk

Graduate Theses and Dissertations

Recent experimental progress has realized strong, efficient coupling of effective two level systems to waveguides. We study the scattering of multimode photons from such emitters coupled losslessly to the confined geometry of a one dimensional waveguide. We develop novel techniques for describing the scattered state of both single and multi-photon wavepackets and explore how such wavepackets interact with arrays of emitters coupled to a one dimensional waveguide. Finally, we apply these techniques and analyze the capability of two particular systems to act as a quantum conditional logic gate.