Optics Commons^™

Investigation Of Complex Refractive Index Of Grad Phene Oxide Using Polarisation Response Of Graphene Oxide-Coated Planarizeoptical Waveguide, Soon Xin Gan

Student Works (2020-2029)

Since a single atomic layer of carbon, also as known as graphene is being successfully exfoliated from 3D graphite, intense research on graphene and its derivative begins. Among them, graphene oxide (GO) is considered one of the most prominent candidates in the category of graphene derivatives for the application of electronic, optoelectronic and photonics. However, although GO has been applied in many applications like saturable absorbers of Q-switch laser and optical limiters for eye protection, its intrinsic optical properties especially complex refractive index reported so far still has a large deviation. Also, most of the optical characterization research on GO …

Organic Materials As Saturable Absorber For Pulse Generation At Telecommunication Window, Mohammed Hussein Sameer Salam M.H.

Student Works (2020-2029)

This thesis demonstrates several types of fiber lasers based on newly developed organic materials as saturable absorbers (SAs). We used these SAs in all-fiber based erbium-doped fiber laser (EDFL) ring cavity to produce Q-switched and mode-locked pulses at telecommunication window, at ~ 1560 nm. Three different organic materials were used in this thesis: Bis[2-(4,6-difluorophenyl)pyridinato-C2 ,N](picolinato)iridium(III) (FIrpic), bis(8-hydroxyquinoline)zinc (Znq2) and Tris(8-hydroxyquinoline)aluminum (Alq3). Finding new materials is still one of the defining characteristics of nonlinear optics field, as the rapid development of SAs has provided several new opportunities for nonlinear optics. Throughout this work, organic material showed a very interesting performance in …

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 …

Generation Of Correlated Dual Frequency Combs With Pm Fiber Lasers For High-Precision Metrology, Hanieh Afkhamiardakani

Optical Science and Engineering ETDs

Intracavity Phase Interferometry (IPI) using two correlated, counter-propagating frequency combs (pulse trains) in mode-locked lasers has evolved into a powerful technique for high-precision metrology. In this method a physical parameter to be measured imparts a phase shift onto a pulse circulating in the laser cavity. Inside a laser cavity, that phase shift becomes a frequency shift (phase shift/round-trip time) applied to the whole frequency comb created by this pulse as it exits the cavity at each round-trip. This frequency shift is measured by interfering this comb with a reference comb created by a reference pulse circulating in the same mode-locked …

Improved Antimicrobial Properties Of Silver Nanoparticles With Methylene Blue, Ermek Belekov

Masters Theses & Specialist Projects

Photosensitizing agents are the cornerstone of photodynamic therapy (PDT) that play essential role in deactivation process of multidrug resistant pathogens and tumor treatments. In this work we studied a photosensitizing agent made from mixture of silver nanoparticles (Ag NPs) and methylene blue (MB) which possess improved important characteristics like high photostability and high singlet oxygen yield. Ag NPs were synthesized by pulsed laser ablation technique in different aqueous solutions like Polyvinylpyrrolidone (PVP), citrate and Deionized (DI) water. The synthesized Ag NPs were characterized in depth using with transmission electron microscopy (TEM), UVVisible (UV-Vis), and photoluminescence (PL) spectra. Ag NPs were …

Radiation-Balanced Fiber Lasers And Amplifiers, Esmaeil Mobini Souchelmaei Mr

Optical Science and Engineering ETDs

Over the past decades, high-power fiber lasers and amplifiers have been extensively under research to achieve higher output powers. However, temperature rise in the core of fiber lasers and amplifiers has been a big issue in power-scaling. Radiation-balancing is a viable technique introduced for effective heat mitigation in lasers and amplifiers by S. Bowman in 1995. Radiation-balancing relies on solid-state laser cooling as a self-cooling mechanism to mitigate the generated heat in lasers and amplifiers. To implement the mentioned idea in fiber lasers and amplifiers, a set of issues should be scrutinized; (i) the amenability of silica glass (as the …

Quantum Two-Photon Laser In Kerr-Like Medium, Ahmed Mathkoor Faisal Hamood

Student Works (2020-2029)

In this thesis, we studied the Kerr nonlinearity effects on nonclassicality and statistics of the laser field besides the effects of detuning, injection rate, and intensity-dependent coupling (IDC). We developed a quantum theory of light generated from a two-photon laser (TPL) with nonlinear Kerr-like medium in a laser dissipative cavity. The full quantum mechanical approach with the density matrix of the particle-field system is used to derive the TPL master equation based on Scully-Lamb’s quantum theory of laser. Various dynamical operators of interest for the cavity field are calculated analytically and computed numerically. The sophisticated computational program was developed to …

Turbulence Profiling Using Pupil Plane Wavefront Data Derived Fried Parameter Values For A Dynamically Ranged Rayleigh Beacon, Steven M. Zuraski, Elizabeth Beecher, Jack E. Mccrae, Steven T. Fiorino

Faculty Publications

Long-range optical imaging applications are typically hindered by atmospheric turbulence. The effect of turbulence on an imaging system can manifest itself as an image blur effect usually quantified by the phase distortions present in the system. The blurring effect can be understood on the basis of the measured strength of atmospheric optical turbulence along the propagation path and its impacts on phase perturbation statistics within the imaging system. One method for obtaining these measurements is by the use of a dynamically ranged Rayleigh beacon system that exploits strategically varied beacon ranges along the propagation path, effectively obtaining estimates of the …

Measurements Of Optical Turbulence Over 149-Km Path, Jack E. Mccrae, Santasri Bose-Pillai, Steven T. Fiorino, Aaron J. Archibald, Joel Meoak, Brannon Elmore, Thomas Kesler, Christopher A. Rice

Faculty Publications

An experiment was conducted to study turbulence along a 149-km path between the Mauna Loa and Haleakala mountain tops using digital cameras and light-emitting diode (LED) beacons. Much of the path is over the ocean, and a large portion of the path is 3 km above sea level. On the Mauna Loa side, six LED beacons were placed in a roughly linear array with pair spacings from 7 to 62 m. From the Haleakala side, a pair of cameras separated by 83.8 cm observed these beacons. Turbulence along the path induces tilts on the wavefronts, which results in displacements of …

Wave-Optics Investigation Of Turbulence Thermal Blooming Interaction: I. Using Steady-State Simulations, Mark F. Spencer

Faculty Publications

Part I of this two-part paper uses wave-optics simulations to look at the Monte Carlo averages associated with turbulence and steady-state thermal blooming (SSTB). The goal is to investigate turbulence thermal blooming interaction (TTBI). At wavelengths near 1 μm, TTBI increases the amount of constructive and destructive interference (i.e., scintillation) that results from high-power laser beam propagation through distributed-volume atmospheric aberrations. As a result, we use the spherical-wave Rytov number and the distortion number to gauge the strength of the simulated turbulence and SSTB. These parameters simplify greatly given propagation paths with constant atmospheric conditions. In addition, we use the …

Wave-Optics Investigation Of Turbulence Thermal Blooming Interaction: Ii. Using Time-Dependent Simulations, Mark F. Spencer

Faculty Publications

Part II of this two-part paper uses wave-optics simulations to look at the Monte Carlo averages associated with turbulence and time-dependent thermal blooming (TDTB). The goal is to investigate turbulence thermal blooming interaction (TTBI). At wavelengths near 1 μm, TTBI increases the amount of constructive and destructive interference (i.e., scintillation) that results from high-power laser beam propagation through distributed-volume atmospheric aberrations. As a result, we use the spherical-wave Rytov number, the number of wind-clearing periods, and the distortion number to gauge the strength of the simulated turbulence and TDTB. These parameters simply greatly given propagation paths with constant atmospheric conditions. …

Implications Of Four-Dimensional Weather Cubes For Improved Cloud-Free Line-Of-Sight Assessments Of Free-Space Optical Communications Link Performance, Steven T. Fiorino, Santasri Bose-Pillai, Jaclyn Schmidt, Brannon Elmore, Kevin J. Keefer

Faculty Publications

We advance the benefits of previously reported four-dimensional (4-D) weather cubes toward the creation of high-fidelity cloud-free line-of-sight (CFLOS) beam propagation for realistic assessment of autotracked/dynamically routed free-space optical (FSO) communication datalink concepts. The weather cubes accrue parameterization of optical effects and custom atmospheric resolution through implementation of numerical weather prediction data in the Laser Environmental Effects Definition and Reference atmospheric characterization and radiative transfer code. 4-D weather cube analyses have recently been expanded to accurately assess system performance (probabilistic climatologies and performance forecasts) at any wavelength/frequency or spectral band in the absence of field tests and employment data. The …

Demonstration Of A Distributed Bragg Reflector For Polyvinylcarbazole And Cadmium Sulfide Layers: Modeling And Comparison To Experimental Results, Javier E. Hasbun, L. Ajith Desilva

Georgia Journal of Science

Light wave propagation in a periodically stratified medium has many applications in physics, mathematics, and engineering. The subject is of interest to students, teachers, and researchers, as it presents a great opportunity to focus on principles of optics and to understand the basics of mathematical modeling. A complete theory of wave propagation can be derived using Born’s optics theory. We employed that theory to determine the reflectivity of a one-dimensional distributed Bragg reflector (DBR) and do simulations using MATLAB. A DBR is a photonic crystal consisting of alternating layers of materials with different refractive indices. In this study, we modeled …

Fourier Propagation Tool For Aberration Analysis And A Point Spread Function Calculation Of Systems With Curved Focal Planes, Stephen C. Cain

Faculty Publications

This paper describes a new Fourier propagator for computing the impulse response of an optical system with a curved focal plane array, while including terms ignored in Fresnel and Fraunhofer calculations. The propagator includes a Rayleigh-Sommerfeld diffraction formula calculation from a distant point through the optical system to its image point predicted by geometric optics on a spherical surface. The propagator then approximates the neighboring field points via the traditional binomial approximation of the Taylor series expansion around that field point. This technique results in a propagator that combines the speed of a Fourier transform operation with the accuracy of …

Statistical Photo-Calibration Of Photo-Detectors For Radiometry Without Calibrated Light Sources Comprising An Arithmetic Unit To Determine A Gain And A Bias From Mean Values And Variance Values, Adrian M. Catarius, Nicholas Yielding, Stephen C. Cain, Michael D. Seal

AFIT Patents

Calibration of a radiometry system uses a readout circuit of a photo-detector to provide first and second measurements collected over first and second integration times, respectively, where the first and second measurements are related to a photonic input to the photo-detector by a gain and a bias. First mean and variance values are computed for a plurality of first measurements. Second mean and variance values are computed for a plurality of second measurements. The gain and bias are determined from the first and second mean values and the first and second variance values without the use of a calibrated source. …

Design Of A 5 Degree Of Freedom Kinematic Stage For The Dual Crystal Backlighter Imager Diagnostic, Nicholas Nguyen

Master's Theses

The National Ignition Facility (NIF) is home to the world’s most energetic laser. The facility is one of the leading centers in inertial confinement fusion (ICF) experiments to research and understand sustainable fusion energy. To fully document and understand the physics occurring during experiments, precise diagnostics are used for a wide range of purposes. One diagnostic, the crystal backlighter imager (CBI), allows for X-ray imaging of the target at late stages of its implosion.

The aim of this project was to increase the current capabilities of the CBI diagnostic with the addition of a second crystal. This thesis focuses on …

Data Assimilation For Conductance-Based Neuronal Models, Matthew Moye

Dissertations

This dissertation illustrates the use of data assimilation algorithms to estimate unobserved variables and unknown parameters of conductance-based neuronal models. Modern data assimilation (DA) techniques are widely used in climate science and weather prediction, but have only recently begun to be applied in neuroscience. The two main classes of DA techniques are sequential methods and variational methods. Throughout this work, twin experiments, where the data is synthetically generated from output of the model, are used to validate use of these techniques for conductance-based models observing only the voltage trace. In Chapter 1, these techniques are described in detail and the …

Quantitative Fluorescence Imaging For Investigation And Treatment Of Disease, Lemoyne Michael Habimana-Griffin

McKelvey School of Engineering Graduate Student Theses & Dissertations

Molecular imaging is a powerful tool that enables interrogation of basic molecular mechanisms, diagnosis of disease, guidance of therapeutic modalities and monitoring of treatment response. Among the various imaging modalities, optical imaging is particularly suited for preclinical molecular imaging owing to its high sensitivity, lack of exposure to ionizing radiation, low cost, portability and scalability of imaging from the microscopic to macroscopic scale. In particular, fluorescence molecular tomography (FMT) provides quantitative 3D reconstructions of fluorescence distributions down to picomole quantities allowing for whole animal molecular imaging. In this work, FMT is applied to detect disease-specific molecular probes, to monitor and …

The Primary Volatile Composition Of Comet C/2015 Er61 (Panstarrs), Aaron Butler

Theses

In the outer edges of the solar system exist two regions: the Kuiper belt and Oort cloud. These two regions have a high amount of icy bodies (comets) orbiting the Sun. Comets located within the Oort cloud and Kuiper belt contain an ancient codex to the solar systems contents, before the formation of our solar system. Presented are near-infrared, high-resolution (λ/Δλ ~40000) data obtained from the immersion-grating echelle spectrograph iSHELL at the 3m NASA Infrared Telescope Facility (IRTF) in Maunakea, Hawaii of the Oort cloud comet C/2015 ER61 (PANSTARRS). Observations took place on April 15 and 17 in 2017 while …

Laser Photoionization Spectroscopy Of Rydberg And Autoionization States Of Rare-Earth Atoms., Nafas Eshkabilov, Sh. R. Xaydarov, Anvar Kurbaniyazov

Scientific Journal of Samarkand University

Systematic studies of Rydberg and autoionization states of rare-earth atoms are carried out. The exact values of the ionization potentials of all lanthanides were determined, and the relationships between the ionization potential of atoms and the number of lost valence electrons during multistage laser photoionization were investigated. The physical mechanisms of the formation of spike and smooth, asymmetric autoionization resonances in near-threshold and long-range autoionization spectra of rare-earth atoms are established.