Optics Commons^™

Optical Theory Improvements To Space Domain Awareness, Tyler J. Hardy

Theses and Dissertations

This dissertation focuses on increasing the ability to detect space objects and increase Space Domain Awareness (SDA) with space surveillance sensors through image processing and optical theory. SDA observations are collected through ground-based radar and optical systems as well as space based assets. This research focuses on a ground-based optical telescope system, the Space Surveillance Telescope (SST). By increasing the number of detectable Resident Space Objects (RSOs) through image processing, SDA capabilities can be expanded. This is accomplished through addressing two main degrading factors present in typical SDA sensors; spatial undersampling in the collected data and noise models and assumptions …

Quantum Enigma Machine: Experimentally Demonstrating Quantum Data Locking, Daniel J. Lum, John C. Howell, M. S. Allman, Thomas Gerrits, Varun B. Verma, Sae Woo Nam, Cosmo Lupo, Seth Lloyd

Mathematics, Physics, and Computer Science Faculty Articles and Research

Shannon proved in 1949 that information-theoretic-secure encryption is possible if the encryption key is used only once, is random, and is at least as long as the message itself. Notwithstanding, when information is encoded in a quantum system, the phenomenon of quantum data locking allows one to encrypt a message with a shorter key and still provide information-theoretic security. We present one of the first feasible experimental demonstrations of quantum data locking for direct communication and propose a scheme for a quantum enigma machine that encrypts 6 bits per photon (containing messages, new encryption keys, and forward error correction bits) …

Photonicstd-2d: Modeling Light Scattering In Periodic Multilayer Photonic Structures, Alexey Bondarev, Shaimaa Azzam, Zhaxylyk Kudyshev, Alexander V. Kildishev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Efficient modeling of electromagnetic processes in optical and plasmonic metamaterials is important for enabling new and exciting ways to manipulate light for advanced applications. In this work, we put together a tool for numerical simulation of propagation of normally incident light through a nanostructured multilayer composite material. The user builds a unit cell of a given material layer-by-layer starting from a substrate up to a superstrate, splitting each layer further into segments. The segments are defined by width and material -- dielectric, metal or active medium. Simulations are performed with the finite difference time domain (FDTD) method. A database of …

Designs And Reliability Evaluations Of A Scattered Light Measurement System, Kang-Min Lee

Graduate Theses - Physics and Optical Engineering

The purpose of my work was to develop an in-plane stray light measurement system having the advantage of being easily applicable in both motion control and optical configurations. First of all, mechanical designs were conducted based on both 3D modeling and structural analysis through a finite element method (FEM). Optical configurations for both the incident source and the detector were designed to achieve minimum observed source convergence angle of the system. The control panel and micro stepping system were programmed for automated measurement. Finally, the designed system was calibrated and aligned. In order to evaluate the system reliability for scatter …

Chiral Light Intrinsically Couples To Extrinsic/Pseudo-Chiral Metasurfaces Made Of Tilted Gold Nanowires, Alessandro Belardini, Marco Centini, Grigore Leahu, David C. Hooper, Roberto Li Voti, Eugenio Fazio, Joseph W. Haus, Andrew Sarangan, Ventsislav K. Valev, Concita Sibilia

Electro-Optics and Photonics Faculty Publications

Extrinsic or pseudo-chiral (meta)surfaces have an achiral structure, yet they can give rise to circular dichroism when the experiment itself becomes chiral. Although these surfaces are known to yield differences in reflected and transmitted circularly polarized light, the exact mechanism of the interaction has never been directly demonstrated. Here we present a comprehensive linear and nonlinear optical investigation of a metasurface composed of tilted gold nanowires. In the linear regime, we directly demonstrate the selective absorption of circularly polarised light depending on the orientation of the metasurface. In the nonlinear regime, we demonstrate for the first time how second harmonic …

Nanophotonics For Dark Materials, Filters, And Optical Magnetism, Mengren Man

Open Access Dissertations

Research on nanophotonic structures for three application areas is described, a near perfect optical absorber based on a graphene/dielectric stack, an ultraviolet bandpass filter formed with an aluminum/dielectric stack, and structures exhibiting homogenizable magnetic properties at infrared frequencies. The graphene stack can be treated as a effective, homogenized medium that can be designed to reflect little light and absorb an astoundingly high amount per unit thickness, making it an ideal dark material and providing a new avenue for photonic devices based on two-dimensional materials. Another material stack arrangement with thin layers of metal and insulator forms a multi-cavity filter that …

Investigation Of Cellular Microenvironments And Heterogeneity With Biodynamic Imaging, Daniel Alexander Merrill

Open Access Dissertations

Imaging of biological tissue in a relevant environment is critical to accurately assessing the effectiveness of chemotherapeutic agents in combatting cancer. Though many three-dimensional (3D) culture models exist, conventional in vitro assays continue to use two-dimensional (2D) cultures because of the difficulty in imaging through deep tissue. 3D tomographic imaging techniques exist and are being used in the development of 3D efficacy assays. However, most of these assays look at therapy endpoint (dead or living cancer cell count) and do not capture the dynamics of tissue response.

Biodynamic imaging (BDI) is a 3D tomographic imaging and assay technique that uses …

Forward Light Scattering In An Extended Sample Of Cold Atoms, Stetson Roof

Physics Theses & Dissertations

We present results on the forward emitted light from a cold atomic sample of 87Rb. Specifically,we study single-photon superradiance which is characterized by a rapid decay faster than the single atom lifetime with the light preferentially emitted in the forward direction. Additionally, we report measurements on its counterpart, the cooperative Lamb shift. The results are interpreted using microscopic light scattering theory as well as techniques from classical optics. The comparison of the two analytical techniques provides a new perspectiveon what is meant by cooperative and collective scattering effects in cold atomic physics.

Study Of Plasmonic Properties Of The Gold Nanorods In The Visible To Near Infrared Light Regime, Pijush Kanti Ghosh

Graduate Theses and Dissertations

Nanostructures of noble metals show unique plasmonic behavior in the visible to near-infrared light range. Gold nanostructures exhibit a particularly strong plasmonic response for these wavelengths of light. In this study we have investigated optical enhancement and absorption of gold nanorods with different thickness using finite element method simulations. This study reports on the resonance wavelength of the sharp-corner and round-corner rectangles of constant length 100 nm and width 60 nm. The result shows that resonance wavelength depends on the polarization of the incident light; there also exists a strong dependence of the optical enhancement and absorption on the thickness …

Instrumentation Of A Self-Correcting Data Acquisition System For Ultrafast Lasers, Fabricio S. Marin

DePaul Discoveries

Optical phenomenon in semiconductors and other light-sensitive materials typically happen at very short time durations, and require instruments capable of measuring time resolutions on the order of nanoseconds to femtoseconds. Electronics can only measure up to nanosecond-time lengths. The purpose of this summer research project is to design a system capable of achieving variable time delays with resolutions up to femtosecond range to use in time-resolved experiments with the pump-probe technique. The time delay is achieved using a delay stage driven by a micro stepper-motor which moves in variable increments while an encoder counts the steps and tells a computer …

Surface Roughness Effects On Light Propagation In Optical Light Pipes, Youngjin Park

Graduate Theses - Physics and Optical Engineering

Solid- and hollow-core light pipes are commonly employed to shape the intensity profile of high power lasers for applications in various technology industries such as the automobile, medical, and communications. There are several loss mechanisms present in solid-core glass and polymer light pipes, including absorption, bulk scattering in the material, surface scattering at the material-air interface, and Fresnel Loss at the material-air interface. Fresnel reflection and surface scattering losses typically dominate over other loss mechanisms in solid-core light pipes made of high quality optical materials. In order to analyze the losses in the light pipe, an approximate model is developed …

Recursive Non-Local Means Filter For Video Denoising With Poisson-Gaussian Noise, Redha A. Almahdi, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

In this paper, we describe a new recursive Non-Local means (RNLM) algorithm for video denoising that has been developed by the current authors. Furthermore, we extend this work by incorporating a Poisson-Gaussian noise model. Our new RNLM method provides a computationally efficient means for video denoising, and yields improved performance compared with the single frame NLM and BM3D benchmarks methods. Non-Local means (NLM) based methods of denoising have been applied successfully in various image and video sequence denoising applications. However, direct extension of this method from 2D to 3D for video processing can be computationally demanding. The RNLM approach takes …

Analysis Of Various Classification Techniques For Computer Aided Detection System Of Pulmonary Nodules In Ct, Barath Narayanan Narayanan, Russell C. Hardie, Temesguen Messay

Electrical and Computer Engineering Faculty Publications

Lung cancer is the leading cause of cancer death in the United States. It usually exhibits its presence with the formation of pulmonary nodules. Nodules are round or oval-shaped growth present in the lung. Computed Tomography (CT) scans are used by radiologists to detect such nodules. Computer Aided Detection (CAD) of such nodules would aid in providing a second opinion to the radiologists and would be of valuable help in lung cancer screening. In this research, we study various feature selection methods for the CAD system framework proposed in FlyerScan. Algorithmic steps of FlyerScan include (i) local contrast enhancement (ii) …

Emergence Of Collective Light Scattering In Atomic 87Rb Samples, Kasie Jean Kemp

Physics Theses & Dissertations

Over the past half century, atomic ensembles have been used to create sensors, clocks, and quantum information systems. As these devices become more compact, and as the number of atoms increases to improve the sensitivity for detection, the atomic samples are increasing in density and optical depth. As such, the spectroscopic properties of the atomic media are modified due to interactions among the particles in the ensemble. We report investigation of near-resonance light scattering from a cold atomic sample of 87Rb. Initially prepared in a magneto-optical trap, the atoms are loaded into a far-off-resonance optical dipole trap (FORT) in which …

Microcavity Enhanced Raman Scattering, Benjamin James Petrak

USF Tampa Graduate Theses and Dissertations

Raman scattering can accurately identify molecules by their intrinsic vibrational frequencies, but its notoriously weak scattering efficiency for gases presents a major obstacle to its practical application in gas sensing and analysis. This work explores the use of high finesse (50 000) Fabry-Pérot microcavities as a means to enhance Raman scattering from gases. A recently demonstrated laser ablation method, which carves out a micromirror template on fused silica--either on a fiber tip or bulk substrates-- was implemented, characterized, and optimized to fabricate concave micromirror templates ~10 µm diameter and radius of curvature. The fabricated templates were coated with a high-reflectivity …

Experimental Demonstration Of The Microscopic Origin Of Circular Dichroism In Two-Dimensional Metamaterials, Alexander B. Khanikaev, N. Arju, Z. Fan, D. Purtseladze, F. Lu, J. Lee, P. Sarriugarte, M. Schnell, R. Hillenbrand, M. A. Belkin, G. Shvets

Publications and Research

Optical activity and circular dichroism are fascinating physical phenomena originating from the interaction of light with chiral molecules or other nano objects lacking mirror symmetries in three-dimensional (3D) space. While chiral optical properties are weak in most of naturally occurring materials, they can be engineered and significantly enhanced in synthetic optical media known as chiral metamaterials, where the spatial symmetry of their building blocks is broken on a nanoscale. Although originally discovered in 3D structures, circular dichroism can also emerge in a two-dimensional (2D) metasurface. The origin of the resulting circular dichroism is rather subtle, and is related to non-radiative …

Particle Image Velocimetry And Analysis Methods Using Cleanly Seeded Particles In Supersonic Flow, Paul A. Gulotta

Theses and Dissertations

Particle Image Velocimetry (PIV) was successfully conducted in the Air Force Research Lab Mach 3/ Mach 6 Facility (M3M6F) for the first time. Particle response experiments evaluating the performance of dry ice particles across an oblique shock wave were conducted using a 15 degree half-wedge in nominal Mach 3 flow. Solid carbon dioxide particles are generated through rapid expansion of liquid carbon dioxide via a small nozzle within a simple shroud tube or a tube containing static mixing elements. Particles are injected directly into the settling chamber of the Mach 3 tunnel. The particle response of carbon dioxide particles is …

Phase Gradient Algorithm Method For 3-D Holographic Ladar Imaging, Jason W. Stafford, Bradley D. Duncan, David J. Rabb

Electro-Optics and Photonics Faculty Publications

3-D holographic ladar uses digital holography with frequency diversity to add the ability to resolve targets in range. A key challenge is that since individual frequency samples are not recorded simultaneously, differential phase aberrations may exist between them making it difficult to achieve range compression. We describe steps specific to this modality so that phase gradient algorithms (PGA) can be applied to 3-D holographic ladar data for phase corrections across multiple temporal frequency samples. Substantial improvement of range compression is demonstrated with a laboratory experiment where our modified PGA technique is applied. Additionally, the PGA estimator is demonstrated to be …

Photoemission Electron Microscopy For Analysis Of Dielectric Structures And The Goos-Hänchen Shift, Theodore Axel Stenmark

Dissertations and Theses

Photoemission Electron Microscopy (PEEM) is a versatile tool that relies on the photoelectric effect to produce high-resolution electron images. Ultrafast pulse lasers allow for multi-photon PEEM where multiple visible or IR photons excite a single electron in a nonlinear process. The photoelectron yield in both cases is related to the near-field region of electromagnetic fields at the surface of the sample. We use this ability here to analyze wave propagation in a linear dielectric waveguide with wavelengths of 410 nm and 780 nm. The propagation constant of the waveguide can be extracted from interference patterns created by light propagating in …

Optical Bistability In A Vcsel Coupled To Serially-Connected Pin Photodiodes Quantizer Device, Sanaz Faryadras

Graduate Theses - Physics and Optical Engineering

In this work we investigated the structure and performance of vertical cavity surface emitting lasers (VCSEL) which will be used in building an optical quantizer. In any p-i-n structure, capacitance is the most important factor in deciding the highest modulation speed. Therefore, components with smaller capacitance would show higher switching speed. A novel electrical quantizer was constructed using two identical 850 nm Finisar VCSELs, which could manifest electrical switching up to 1.4 MHz. Also, a new electrical quantizer was built with two Eudyna PIN photodiodes (PD-PD), which works at higher frequencies up to 8 MHz, comparing to previous works. The …

Effect Of Fluid Suction On An Oscillatory Mhd Channel Flow With Heat Transfer, N. Ahmed, A. H. Sheikh, D. P. Barua

Applications and Applied Mathematics: An International Journal (AAM)

Magnetohydrodynamics (MHD) is generally concerned with the study of the magnetic properties (behaviour) of electrically conducting fluids (plasmas, liquid metals etc.) moving in an electromagnetic field. The importance of the concept of MHD in various fields such as astrophysics, bio-medical research, missile technology and geophysics motivates the modelling and investigation of MHD flow and transport problems. The role of fluid suction is paramount in laminar flow control and has wide applications in fields such as aeronautical engineering, automobile engineering and rocket science. This fact inspires the study of the effects of fluid suction in flow and transport models. Time dependent …

Spontaneous Parametric Down-Conversion In A Beta Barium Borate Crystal, Nicholas Williams

Physics

No abstract provided.

Laminar Flame Combustion Diagnostics Using Imaging Fourier Transform Spectroscopy, Michael R. Rhoby

Theses and Dissertations

Laminar flames are an important tool in combustion diagnostics with a host of pre-existing experimental research methods. Currently, however, no method captures time-resolved scalar profile estimates of temperature, and major species concentrations with a single measurement. This work provides IFTS with the capability to measure time-resolved 3D imaging of scalar values in laminar axisymmetric flames. This will make IFTS a useful tool for understanding combustion phenomenon, validating chemical kinetic models, verifying numerical simulations, and system performance estimate. Two algorithms are presented. The first reconstructs spectra as a function of flame period. Through selectively averaging over an ensemble of measurements, interferograms …

Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati

USF Tampa Graduate Theses and Dissertations

In this dissertation, advances in the fields of Photonics, and Plasmonics, and specifically, single cell analysis and waveguide sensing will be addressed. The first part of the dissertation is on Finite Difference Time Domain (FDTD) optimization and experimental demonstration of a nano-scale instrument that allows sensing at the cellular and subcellular levels. A new design of plasmonic coupler into a nanoscale waveguide is proposed and optimized using FDTD simulations. Following this, a subcellular nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted fluorescent light for detailed spectrum analysis is fabricated and tested. The nanoendoscope has …

Weak-Value Amplification Of The Fast-Light Effect In Rubidium Vapor, Mohammad Mirhosseini, Gerardo I. Viza, Omar S. Magaña-Loaiza, Mehul Malik, John C. Howell, Robert W. Boyd

Mathematics, Physics, and Computer Science Faculty Articles and Research

We use weak-value amplification to enhance the polarization-sensitive fast-light effect from induced Raman absorption in hot rubidium vapor. We experimentally demonstrate that projecting the output signal into an appropriate polarization state enables a pulse advancement of 4.2μs, which is more than 15 times larger than that naturally caused by dispersion. More significantly, we show that combining weak-value amplification with the dispersive response of an atomic system provides a clear advantage in terms of the maximum pulse advance achievable for a given value of loss. This technique has potential applications for designing novel quantum-information-processing gates and optical buffers for telecommunication systems.

Cross-Phase Modulation Enhancement Via A Resonating Cavity: Semiclassical Description, Julián Martínez-Rincón, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We evaluate the advantages of performing cross-phase modulation (XPM) on a very-far-off-resonance atomic system. We consider a ladder system with a weak (few-photon level) control coherent field imparting a conditional nonlinear phase shift on a probe beam. We find that by coupling to an optical resonator, the optimal XPM is enhanced proportional to the finesse of the resonator by a factor of ��/4��. We present a semiclassical description of the system and show that the phenomenon is optimal in the self-defined condition of off-resonance effective cooperativity equal to one.

Digital Integral Cloaking, Joseph S. Choi, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

Toward the goal of achieving broadband and omnidirectional invisibility, we propose a method for practical invisibility cloaking. We call this “digital cloaking,” where space, angle, spectrum, and phase are discretized. Experimentally, we demonstrate a two-dimensional (2D) planar, ray optics, digital cloak by using lenticular lenses, similar to “integral imaging” for three-dimensional (3D) displays. Theoretically, this can be extended to a good approximation of an “ideal” 3D cloak. With continuing improvements in commercial digital technology, the resolution limitations of a digital cloak can be minimized.

Light-Activated Photocurrent Degradation And Self-Healing In Perovskite Solar Cells, Wanyi Nie, Jean-Christophe Blancon, Amanda J. Neukirch, Kannatassen Appavoo, Hsinhan Tsai, Manish Chhowalla, Muhammad A. Alam, Matthew Y. Sfeir, Claudine Katan, Jacky Even, Sergei Tretiak, Jared J. Crochet, Gautam Gupta, Aditya D. Mohite

Publications and Research

Solution-processed organometallic perovskite solar cells have emerged as one of the most promising thin-film photovoltaic technology. However, a key challenge is their lack of stability over prolonged solar irradiation. Few studies have investigated the effect of light soaking on hybrid perovskites and have attributed the degradation in the optoelectronic properties to photochemical or field-assisted ion migration. Here we show that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states. However, the devices can self-heal completely by resting them in the dark for <1 min or the degradation can be completely prevented by operating the devices at 0°C. We investigate several physical mechanisms to explain the microscopic origin for the formation of these trap states, among which the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

Goggle Augmented Imaging And Navigation System For Fluorescence-Guided Surgery, Suman Bikash Mondal

McKelvey School of Engineering Graduate Student Theses & Dissertations

Surgery remains the only curative option for most solid tumors. The standard-of-care usually involves tumor resection and sentinel lymph node biopsy for cancer staging. Surgeons rely on their vision and touch to distinguish healthy from cancer tissue during surgery, often leading to incomplete tumor resection that necessitates repeat surgery. Sentinel lymph node biopsy by conventional radioactive tracking exposes patients and caregivers to ionizing radiation, while blue dye tracking stains the tissue highlighting only superficial lymph nodes. Improper identification of sentinel lymph nodes may misdiagnose the stage of the cancer. Therefore there is a clinical need for accurate intraoperative tumor and …

Failure Of Surface Color Cues Under Natural Changes In Lighting, David H. Foster, Iván Marín-Franch

MODVIS Workshop

Color allows us to effortlessly discriminate and identify surfaces and objects by their reflected light. Although the reflected spectrum changes with the illumination spectrum, cone photoreceptor signals can be transformed to give useful cues for surface color. But what happens when both the spectrum and the geometry of the illumination change, as with lighting from the sun and sky? Is it possible, as a matter of principle, to obtain reliable cues by processing cone signals alone? This question was addressed here by estimating the information provided by cone signals from time-lapse hyperspectral radiance images of five outdoor scenes under natural …