Optics Commons^™

Interband One- And Two-Photon Absorption Of Polarized Light In Narrow-Gap Crystals, Rustam Yavkachovich Rasulov E.G., V R. Rasulov, B B. Akhmedov, I A. Muminov

Scientific-technical journal

Interband two-photon optical transitions are analyzed, and expressions are obtained for the matrix elements in a narrow-gap crystal depending on the band parameters, degree of polarization, and light frequency. It is shown that the main contribution to two-photon linear-circular dichroism in narrow-gap semiconductors is made by optical transitions proceeding from the subband of light holes to the conduction band.

The dependences of the partial coefficients of interband one- and two-photon absorption of light are obtained, which differ from each other by the types of optical transitions, depending on the frequency and degree of polarization of light in narrow-gap crystals in …

Dipolariton Propagation In A Van Der Waals Tmdc With Ψ-Shaped Channel Guides And Buffered Channel Branches, Patrick Serafin, German Kolmakov

Publications and Research

Using a computational approach based on the driven diffusion equation for a dipolariton wave packet, we simulate the diffusive dynamics of dipolaritons in an optical microcavity embedded with a transition metal dichalcogenide (TMDC) heterogeneous bilayer encompassing a Ψ-shaped channel. By considering exciton dipolaritons, which are a three way superposition of direct excitons, indirect excitons and cavity photons; we are able to drive the dipolaritons in our system by the use of an electric voltage and investigate their diffusive properties. More precisely, we study the propagation of dipolaritons present in a MoSe₂-WS₂ heterostructure, where the dipolariton propagation is …

Fluorescence Spectroscopy For The Determination Of Reconstitution Time Of An In-Vial Lyophilised Product, Khaled Elkassas, Krishnakumar Chullipalliyalil, Michael Mcauliffe, Sonja Vucen, Abina Crean

Cappa Publications

Lyophilisation is a prominent technique used to create stabilised, dried forms of biopharmaceutical formulations. Reconstitution of lyophilised parenteral formulations is a key step prior to patient administration. The accurate determination of reconstitution time is a necessity to aid formulation development and support product quality control. Traditional methods for quantifying reconstitution time involve the visual identification of the endpoint, which has led to variable values reported across studies. In this work, the use of ultra-violet (UV) excited fluorescence spectroscopy as an alternative to the visual quantification of the reconstitution time was investigated. Spectrographic information was collected via a bespoke setup that …

Achieving The Shot-Noise Limit Using Experimental Multi-Shot Digital Holography Data, Douglas E. Thornton, Cameron J. Radosevich, Samuel Horst, Mark F. Spencer

Faculty Publications

In this paper, we achieve the shot-noise limit using straightforward image-post-processing techniques with experimental multi-shot digital holography data (i.e., off-axis data composed of multiple noise and speckle realizations). First, we quantify the effects of frame subtraction (of the mean reference-only frame and the mean signal-only frame from the digital-hologram frames), which boosts the signal-to-noise ratio (SNR) of the baseline dataset with a gain of 2.4 dB. Next, we quantify the effects of frame averaging, both with and without the frame subtraction. We show that even though the frame averaging boosts the SNR by itself, the frame subtraction and the stability …

Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Hengky Chandrahalim, Jonathan W. Smith

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.

Color-Compressive Bilateral Filter And Nonlocal Means For High-Dimensional Images, Christina Karam, Kenjiro Sugimoto, Keigo Hirakawa

Electrical and Computer Engineering Faculty Publications

We propose accelerated implementations of bilateral filter (BF) and nonlocal means (NLM) called color-compressive bilateral filter (CCBF) and color-compressive nonlocal means (CCNLM). CCBF and CCNLM are random filters, whose Monte-Carlo averaged output images are identical to the output images of conventional BF and NLM, respectively. However, CCBF and CCNLM are considerably faster because the spatial processing of multiple color channels are combined into a single random filtering process. This implies that the complexity of CCBF and CCNLM is less sensitive to color dimension (e.g., hyperspectral images) relatively to other BF and NLM methods. We experimentally verified that the execution time …

Deep Learning For Anisoplanatic Optical Turbulence Mitigation In Long-Range Imaging, Matthew A. Hoffmire, Russell C. Hardie, Michael A. Rucci, Richard Van Hook, Barry K. Karch

Electrical and Computer Engineering Faculty Publications

We present a deep learning approach for restoring images degraded by atmospheric optical turbulence. We consider the case of terrestrial imaging over long ranges with a wide field-of-view. This produces an anisoplanatic imaging scenario where turbulence warping and blurring vary spatially across the image. The proposed turbulence mitigation (TM) method assumes that a sequence of short-exposure images is acquired. A block matching (BM) registration algorithm is applied to the observed frames for dewarping, and the resulting images are averaged. A convolutional neural network (CNN) is then employed to perform spatially adaptive restoration. We refer to the proposed TM algorithm as …

Examination Of A Lenseless Setup For Reflective Inverse Diffusion Of Light, John Nguyen

Theses and Dissertations

Reflective inverse diffusion uses spatial light modulators to shape an incident wavefront so that when the wavefront interacts with some diffuse scattering sample, the reflected light will constructively interfere at a single focus. This thesisexamines the efficacy of using a lensless setup against a focal plane setup in achieving reflective inverse diffusion while simultaneously beamsteering. The lensless setup outperformed its counterpart by being able to focus more energy in a region, but failed to achieve the same beamsteering capabilities as the focal plane system. Understanding the flaws behind the lensless setup will be instrumental in creating a setup that can …

Dynamic Holography In Resonant Nonlinear Media: Theory And Application, Jonathan E. Slagle

Theses and Dissertations

Two beam coupling (TBC) is a coherent interaction in which energy is transferred from one laser beam to another and has promising applications in real-time holography and coherent beam combing. We have recently shown efficient degenerate frequency TBC for counter-propagation geometries in isotropic two-photon absorbing media pumped with a nanosecond pulsed laser. When an interference pattern is generated in this media, single and two photon absorption initiates a population redistribution resulting in a holographic grating with the same modulation period and phase initially. However, due to temporal convolution of self- and cross-phase modulation, the grating will begin to shift in …

Optical Study Of 2-D Detonation Wave Stability, Eulaine T. Grodner

Theses and Dissertations

Fundamental optical detonation study of detonations constricted to a 2-d plane propagation, and detonations propagating around a curve. All images were processed using modern image processing techniques. The optical techniques used were shadowgraph, Schlieren, and chemiluminescence. In the 2-Dstraight channels, it was determined wave stability was a factor of cell size. It was also determined the detonation wave thickness (area between the combustion and shockwave) was a factor of how much heat available for the detonation. For the detonations propagating around a curve, it was determined the three main classifications of wave stability were stable, unstable, and detonation wave restart. …

A Comparative Evaluation Of The Fast Optical Pulse Response Of Event-Based Cameras, Tyler J. Brewer

Theses and Dissertations

Event cameras use biologically inspired readout circuit architecture to offer a faster and more efficient method of imaging than traditional frame-based detectors. The asynchronous event reporting circuit timestamps events to 1 microsecond resolution, but latency increases when many pixels are stimulated simultaneously. To characterize this variability, the DAVIS240, DAVIS346, DVXPlorer, and Prophesee Gen3M VGA-CD 1.1 cameras were exposed to single step-function flashes with amplitudes from 9.3-771cd/m², stimulating from 0.0042-100 of pixels. The Median Absolute Deviation of pixel response times ranged between 0 and 6086µs, increasing with the percent of pixels stimulated (PSP). The number of events generated per …

Neuromorphic Vision Sensors For Space-Based Applications, Jessica L. Horn

Theses and Dissertations

This research examines the viability of event-based vision (neuromorphic) sensors for future use on satellites. Outputting single pixel events only when a change in intensity is detected, event-based vision sensors offer a potential low power, low latency, high temporal resolution, and high dynamic range solution as compared to traditional CCD or CMOS camera technology. The commercial off-the-shelf DVS240C sensor, is analyzed to determine if operability is affected by launch conditions and the low Earth space environment through vacuum, thermal vacuum, and vibration tests. No appreciable changes in sensor operation was observed throughout testing. Additionally, the sensor was able to detect …

Independently Controlling Stochastic Field Realization Magnitude And Phase Statistics For The Construction Of Novel Partially Coherent Sources, Milo W. Hyde Iv

Faculty Publications

In this paper, we present a method to independently control the field and irradiance statistics of a partially coherent beam. Prior techniques focus on generating optical field realizations whose ensemble-averaged autocorrelation matches a specified second-order field moment known as the cross-spectral density (CSD) function. Since optical field realizations are assumed to obey Gaussian statistics, these methods do not consider the irradiance moments, as they, by the Gaussian moment theorem, are completely determined by the field’s first and second moments. Our work, by including control over the irradiance statistics (in addition to the CSD function), expands existing synthesis approaches and allows …

Computational Modelling Enables Robust Multidimensional Nanoscopy, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

The following sections are included:

• Present State of Computational Modelling in Fluorescence Nanoscopy

• Recent Contributions to Computational Modelling in Fluorescence Nanoscopy

• Outlook on Computational Modelling in Fluorescence Nanoscopy

• Acknowledgments

• References

Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, Robert J. Collison

Dissertations, Theses, and Capstone Projects

It is common knowledge that metals, alloys and pure elements alike, are lustrous and reflective, the more so when a metal surface is flat, polished, and free from oxidation and surface fouling. However, some metals reflect visible light, in the 380 nm to 740 nm range of wavelengths, much more strongly than others. In particular, some metals reflect wavelengths in certain portions of the ultraviolet (UV), visible, and near-infrared (NIR) regime, let us say 200 nm to 2000 nm, while absorbing light strongly in other segments of this range. There are several factors that account for this difference between various …

Third Harmonic Generation: A Method For Visualizing Myelin In The Murine Cerebral Cortex, Michael Redlich

Dissertations, Theses, and Capstone Projects

Here we present the use of Third Harmonic Generation (THG) for the label-free imaging of myelinated axons in the murine cerebral cortex. Myelin plays an important role in the processes of learning and disease. However, much of the myelin biology research thus far has focused on white matter tracts where myelin is more visible. Much is still unknown, particularly with regard to myelin in gray matter. First, we engage in THG microscopy using an optical parametric oscillator pumped by a titanium-sapphire laser to demonstrate the utility of the technique for imaging myelin in vivo. Second, we investigate the use of …

Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

The emerging field of plasmonics can lead to enhanced light-matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit …

Characterization Of Spatial-Mode Properties In Few-Mode Fiber Bragg Gratings And Its Applications, Muhammad Khairol Annuar Zaini

Student Works (2020-2029)

Recently, few-mode fiber (FMF) has gained much research attention compared to single mode fiber (SMF) due to its capability to overcome the capacity limit. FMF based fiber sensors have many distinctive advantages such as cost efficiency, great sensitivity, and have the ability to employ the spatial dimension for multi-parameter sensing with discrimination capability. In this work, an analytical model has been proposed to investigate the relationship of the resonant wavelength shift of a few-mode FBG (FMFBG) to the axial stress of the FMF. By applying the proposed model, the axial stress of an FMFs was determined. Besides, the polariscopic technique …

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 …

Mutual Interaction Induced Multi-Particle Physics In Qed Systems – Cooperative Spontaneous Emission And Photonic Dimer Enhanced Two-Photon Excitation, Yao Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, the study of quantum electrodynamics (QED) in light-matter interactions has discovered various interesting phenomenons that orient many applications. However, due to the ambient entanglement among photons and atoms, few-particle dynamics remains challenging to analyze precisely and limits the progress in several fields. In few-particle systems, different number of atoms interacting with the light field generates drastically different results, even when there is only a single photon involved in the system. The interference between individual atom’s spontaneous emission wavefunctions can cooperatively alter the effective atom-light coupling strength. Depending on the spatial distance between individual of atoms and the …

On-Chip Silicon Photonic Controllable 2 × 2 Four-Mode Waveguide Switch, Cao Dung Truong, Duy Nguyen Thi Hang, Hengky Chandrahalim, Minh Tuan Trinh

Faculty Publications

Multimode optical switch is a key component of mode division multiplexing in modern high-speed optical signal processing. In this paper, we introduce for the first time a novel 2 × 2 multimode switch design and demonstrate in the proof-of-concept. The device composes of four Y-multijunctions and 2 × 2 multimode interference coupler using silicon-on-insulator material with four controllable phase shifters. The shifters operate using thermo-optic effects utilizing Ti heaters enabling simultaneous switching of the optical signal between the output ports on four quasi-transverse electric modes with the electric power consumption is in order of 22.5 mW and the switching time …

Analysis And Design Of Infrared Fiber Bundles For Large Field-Of-View Thermal Imaging, Cesar A. Lopez-Zelaya

Honors Undergraduate Theses

During the DARPA SCENICC program, J. Ford, et al., demonstrated that CFBs provide a compelling route to compact, wide angle imagers. Monocentric lenses readily provide diffraction-limited images over wide field but onto a hemispherically curved image surface. They demonstrated visible CFBs can be tapered, cut and polished to relay curved images to flat sensors. We have shown that this provides a volumetric imaging efficiency a hundredfold larger than bulk optics can produce; a hundred times the resolution in the same volume or a hundred times less volume for the same resolution. Ford's work leveraged commercial fiber bundles available for the …

Liquid Crystal Flat Optics For Near-Eye Displays, Tao Zhan

Electronic Theses and Dissertations, 2020-2023

Augmented reality (AR) and virtual reality (VR) displays, considered as the next-generation information platform, have shown great potential to revolutionize the way how we interact with each other and the digital world. Both AR and VR are disruptive technologies that can enable numerous applications in education, healthcare, design, training, entertainment, and engineering. Among all the building blocks of these emerging devices, near-eye displays (NEDs) play a critical role in the entire system, through which we can perceive the virtual world as the real one. However, the visual experience offered by existing NED technologies is still far from satisfying the human …

Measurement And Mitigation Of Optical, Recombination And Resistive Losses In Silicon Photovoltaics, Mohammad Jobayer Hossain

Electronic Theses and Dissertations, 2020-2023

Today, most of the photovoltaic cells in the market are made of silicon. Great achievements are being attained every year in terms of reducing the price of this kind of cells and improving their efficiency, reliability and durability. However, further improving the cell performance is a challenging task because of the presence of optical, recombination and resistive loss mechanisms in the cell. This work is focused on the measurement and mitigation of these losses. Mitigation of the optical, recombination and resistive losses at first require quantifying those losses and their impacts on the cell performance metrics accurately. Traditionally, solar cells …

Direct Multiplexing Of Low Order Aberration Modes In A Photopolymerbased Holographic Element For Analog Holographic Wavefront Sensing, Emma Branigan, Suzanne Martin, Matthew Sheehan, Kevin Murphy

Conference Papers

The fabrication of an analog holographic wavefront sensor, capable of detecting the low order defocus aberration, was achieved in an acrylamide-based photopolymer. While other implementations of holographic wavefront sensors have been carried out digitally, this process utilises a recording setup consisting only of conventional refractive elements so the cost and complexity of holographic optical element (HOE) production could be much reduced. A pair of diffraction spots, corresponding to a maximum and minimum amount of defocus, were spatially separated in the detector plane by multiplexing two HOEs with different carrier spatial frequencies. For each wavefront with a known aberration that was …

On The Information Content In Unresolved Imaging, Zhean Shen

Electronic Theses and Dissertations, 2020-2023

Imaging is almost synonymous with optics. Imaging is the process of using light to form a tangible or visible representation, an imitation (imitari) of a material property. There are many situations, however, where one can only aspire to 'sense making' rather than forming an image per se. In other words, objects cannot be directly resolved by conventional intensity-based imaging, a situation commonly referred to as 'unresolved imaging'. However, there is still information retained in other properties of light, which can be exposed by other means. In this thesis I will discuss two typical situations: subwavelength and multiple scattering, which are …

Dales Objects: A Large Scale Benchmark Dataset For Instance Segmentation In Aerial Lidar, Nina M. Singer, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

We present DALES Objects, a large-scale instance segmentation benchmark dataset for aerial lidar. DALES Objects contains close to half a billion hand-labeled points, including semantic and instance segmentation labels. DALES Objects is an extension of the DALES (Varney et al., 2020) dataset, adding additional intensity and instance segmentation annotation. This paper provides an overview of the data collection, preprocessing, hand-labeling strategy, and final data format. We propose relevant evaluation metrics and provide insights into potential challenges when evaluating this benchmark dataset. Finally, we provide information about how researchers can access the dataset for their use at go.udayton.edu/dales3d.

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.

Multi-Functional Fluorescence Microscopy Via Psf Engineering For High-Throughput Super-Resolution Imaging, Jinhan Ren

Electronic Theses and Dissertations, 2020-2023

Image-based single cell analysis is essential to study gene expression levels and subcellular functions with preserving the native spatial locations of biomolecules. However, its low throughput has prevented its wide use to fundamental biology and biomedical applications which require large cellular populations in a rapid and efficient fashion. Here, we report a 2.5D microcopy (2.5DM) that significantly improves the image acquisition rate while maintaining high-resolution and single molecule sensitivity. Unlike serial z-scanning in conventional approaches, volumetric information is simultaneously projected onto a 2D image plane in a single shot by engineering the fluorescence light using a novel phase pattern. The …

Development Of Quantitative Intensity-Based Single-Molecule Assays, Benjamin Croop

Electronic Theses and Dissertations, 2020-2023

Fluorescence microscopy has emerged as a popular and powerful tool within biology research, owing to its exceptional signal contrast, specificity, and the versatility of the various microscope designs. Fluorescence microscopy has been used to study samples across orders of magnitude in physical scale ranging from tissues to cells, down to single-molecules, and as such has led to breakthroughs and new knowledge in a wide variety of research areas. In particular, single-molecule techniques are somewhat unique in their ability to study biomolecules in their native state, which enables the visualization of short-lived interactions and rare events which can be highly relevant …