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Air Force Institute of Technology

2017

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Articles 1 - 30 of 32

Full-Text Articles in Physics

Power-Law Schell-Model Sources, Milo W. Hyde Iv Nov 2017

Power-Law Schell-Model Sources, Milo W. Hyde Iv

Faculty Publications

A new type of Schell-model source is developed that has a spectral degree of coherence, or spatial power spectrum, which is described by a power-law function. These power-law sources generally produce cusped, or peaked far-zone spectral density patterns making them potentially useful in directed energy applications. The spectral degrees of coherence, spatial power spectra, and spatial coherence radii for power-law sources are derived and discussed. Two power-law sources are then synthesized in the laboratory using a liquid crystal spatial light modulator. The experimental spectral densities are compared to the corresponding theoretical predictions to serve as a proof of concept.

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Single-Reference Coupled Cluster Theory For Multi-Reference Problems, Johannes T. Margraf, Ajith Perera, Jesse J. Lutz, Rodney J. Bartlett Nov 2017

Single-Reference Coupled Cluster Theory For Multi-Reference Problems, Johannes T. Margraf, Ajith Perera, Jesse J. Lutz, Rodney J. Bartlett

Faculty Publications

Coupled cluster (CC) theory is widely accepted as the most accurate and generally applicable approach in quantum chemistry. CC calculations are usually performed with single Slater-determinant references, e.g., canonical Hartree-Fock (HF) wavefunctions, though any single determinant can be used. This is an attractive feature because typical CC calculations are straightforward to apply, as there is no potentially ambiguous user input required. On the other hand, there can be concern that CC approximations give unreliable results when the reference determinant provides a poor description of the system of interest, i.e., when the HF or any other single determinant ground state has …

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Use Of A Novel Infrared Wavelength-Tunable Laser Mueller-Matrix Polarimetric Scatterometer To Measure Nanostructured Optical Materials, Jason C. Vap, Stephen E. Nauyoks, Michael R. Benson, Michael A. Marciniak Oct 2017

Use Of A Novel Infrared Wavelength-Tunable Laser Mueller-Matrix Polarimetric Scatterometer To Measure Nanostructured Optical Materials, Jason C. Vap, Stephen E. Nauyoks, Michael R. Benson, Michael A. Marciniak

Faculty Publications

Nanostructured optical materials, for example, metamaterials, have unique spectral, directional, and polarimetric properties. Samples designed and fabricated for infrared (IR) wavelengths have been characterized using broadband instruments to measure specular polarimetric transmittance or reflectance as in ellipsometry or integrated hemisphere transmittance or reflectance. We have developed a wavelength-tunable IR Mueller-matrix (Mm) polarimetric scatterometer which uses tunable external-cavity quantum-cascade lasers (EC-QCLs) to tune onto and off of the narrowband spectral resonances of nanostructured optical materials and performed full polarimeteric and directional evaluation to more fully characterize their behavior. Using a series of EC-QCLs, the instrument is tunable over 4.37-6.54 μm wavelengths …

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Special Features Of The Air-To-Space Neutron Transport Problem, Whitman T. Dailey Sep 2017

Special Features Of The Air-To-Space Neutron Transport Problem, Whitman T. Dailey

Theses and Dissertations

Special features of the air-to-space neutron transport problem are identified, characterized, and quantified to provide information on features that should be included in Monte Carlo simulations to obtain accurate predictions. Currently available codes and tools for Monte Carlo neutron transport calculations do not provide an adequate (in accuracy nor precision nor efficiency) framework for practical transport calculations in the context of the air-to-space neutron transport problem. A new Fortran code, High Altitude Transport to Space for Neutrons (HATS-n), is developed and tested to perform high fidelity Monte Carlo neutron transport calculations for this class of problems. Special features of the …

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Laser Heating Of Graphite And Pulsed Laser Ablation Of Titanium And Aluminum, William A. Bauer Sep 2017

Laser Heating Of Graphite And Pulsed Laser Ablation Of Titanium And Aluminum, William A. Bauer

Theses and Dissertations

Tactical missions for laser weapons include a wide variety of targets, increasing the demands on the laser lethality community. New approaches to reducing the dimensionality of laser and materials interactions are necessary to increase predictive capability. Self-contained systematic experimental study was conducted on continuous wave and pulsed laser interaction with graphite, Al, and Ti. The spectroscopy and plume dynamics from the heating and ablation of these materials was examined to characterize laser weapons effects, develop graphite response for thermal protection systems, and provide optical diagnostics for materials processing. Furthermore, analysis of ablated plume velocity distributions shows application of conventional Maxwell-Boltzmann …

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Luminescence In Lithium Borates, Brant T. Kananen Sep 2017

Luminescence In Lithium Borates, Brant T. Kananen

Theses and Dissertations

Spectrometry methods are used to identify and characterize point defects in single crystals of lithium tetraborate (Li2B4O7) and lithium triborate (LiB3O5) doped with silver or copper, and explore the role of these point defects in luminescence. New defects are identified in Ag-doped including: lithium vacancy substitutional-silver-ion defect-pairs (hole trap); isolated lithium vacancies (hole trap); isolated oxygen vacancies (electron trap); interstitial-silver-ion substitutional-silver-ion defect pairs (electron trap); isolated interstitial silver ions (electron trap); and interstitial-silver-ion lithium-vacancy defect pairs (electron trap). Defect models are proposed, and adjustments made to defect models known defects. …

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Three-Dimensional Imaging Of Cold Atoms In A Magneto-Optical Trap With A Light Field Microscope, Gordon E. Lott Sep 2017

Three-Dimensional Imaging Of Cold Atoms In A Magneto-Optical Trap With A Light Field Microscope, Gordon E. Lott

Theses and Dissertations

Imaging of trapped atoms in three dimensions utilizing a light field microscope is demonstrated in this work. Such a system is of interest in the development of atom interferometer accelerometers in dynamic systems where strictly defined focal planes may be impractical. A light field microscope was constructed utilizing a Lytro® Development Kit micro-lens array and sensor. It was used to image fluorescing rubidium atoms in a magneto-optical trap. The three-dimensional (3D) volume of the atoms is reconstructed using a modeled point spread function (PSF), taking into consideration the low magnification (1.25) of the system which changed typical assumptions in the …

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Analysis Of Ar(1s5) Metastable Populations In High Pressure Argon-Helium Gas Discharges, Daniel J. Emmons Ii Sep 2017

Analysis Of Ar(1s5) Metastable Populations In High Pressure Argon-Helium Gas Discharges, Daniel J. Emmons Ii

Theses and Dissertations

Simulations of an argon-helium plasma are performed for two high pressure discharge scenarios to find a uniform, large-volume plasma with Ar(1s5) metastable densities on the order of 1013 cm-3 for use as the ground state in an optically pumped rare gas laser. An analysis of a pulsed direct current discharge is performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Simulations are …

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Synthesis Of Non-Uniformly Correlated Partially Coherent Sources Using A Deformable Mirror, Milo W. Hyde Iv, Santasri Bose-Pillai, Ryan A. Wood Sep 2017

Synthesis Of Non-Uniformly Correlated Partially Coherent Sources Using A Deformable Mirror, Milo W. Hyde Iv, Santasri Bose-Pillai, Ryan A. Wood

Faculty Publications

The near real-time synthesis of a non-uniformly correlated partially coherent source using a low-actuator-count deformable mirror is demonstrated. The statistical optics theory underpinning the synthesis method is reviewed. The experimental results of a non-uniformly correlated source are presented and compared to theoretical predictions. A discussion on how deformable mirror characteristics such as actuator count and pitch affect source generation is also included.

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Fresnel Spatial Filtering Of Quasihomogeneous Sources For Wave Optics Simulations, Milo W. Hyde Iv, Santasri Bose-Pillai Aug 2017

Fresnel Spatial Filtering Of Quasihomogeneous Sources For Wave Optics Simulations, Milo W. Hyde Iv, Santasri Bose-Pillai

Faculty Publications

High-spatial-frequency optical fields or sources are often encountered when simulating directed energy, active imaging, or remote sensing systems and scenarios. These spatially broadband fields are a challenge in wave optics simulations because the sampling required to represent and then propagate these fields without aliasing is often impractical. To address this, two spatial filtering techniques are presented. The first, called Fresnel spatial filtering, finds a spatially band-limited source that, after propagation, produces the exact observation plane field as the broadband source over a user-specified region of interest. The second, called statistical or quasihomogeneous spatial filtering, finds a spatially band-limited source that, …

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On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan Aug 2017

On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan

Faculty Publications

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering-gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the …

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Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles Aug 2017

Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR) is used to directly observe and characterize neutral Mg acceptors (Mg0Ga) in a β-Ga2O3 crystal. These acceptors, best considered as small polarons, are produced when the Mg-doped crystal is irradiated at or near 77 K with x rays. During the irradiation, neutral acceptors are formed when holes are trapped at singly ionized Mg acceptors (Mg−Ga). Unintentionally present Fe3+ (3d5) and Cr3+ (3d3) transition-metal ions serve as the corresponding electron traps. The hole is localized in a nonbonding p orbital on a threefold-coordinated oxygen ion …

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Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross Jul 2017

Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross

Faculty Publications

Results of a method of estimating index of refraction from passive, polarimetric hyperspectral imaging radiance measurements are presented. As off-nadir viewing hyperspectral imaging platforms gain prominence, estimating index of refraction, which is invariant to viewing angle, may prove advantageous to estimating the emissivity, which is not. Results show that index of refraction can be retrieved to within 8% rms error for fused silica and sapphire glass targets, while simultaneously estimating object temperature. The accuracy and self-consistency of this technique for estimating index of refraction are shown to compare favorably to the maximum smoothness temperature–emissivity separation algorithm. Additionally, the results show …

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Target-Based Coherent Beam Combining Of An Optical Phased Array Fed By A Broadband Laser Source, Milo W. Hyde Iv, Jack E. Mccrae, Glenn A. Tyler Jul 2017

Target-Based Coherent Beam Combining Of An Optical Phased Array Fed By A Broadband Laser Source, Milo W. Hyde Iv, Jack E. Mccrae, Glenn A. Tyler

Faculty Publications

The target-based phasing of an optical phased array (OPA) fed by a broadband master oscillator laser source is investigated. The specific scenario examined here considers an OPA phasing through atmospheric turbulence on a rough curved object. An analytical expression for the detected or received intensity is derived. Gleaned from this expression are the conditions under which target-based phasing is possible. A detailed OPA wave optics simulation is performed to validate the theoretical findings. Key aspects of the simulation set-up as well as the results are thoroughly discussed.

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Real-Time Camera Tracking System Using Optical Flow Feature Points, Daniel D. Doyle, Alan L. Jennings, Jonathan T. Black Jul 2017

Real-Time Camera Tracking System Using Optical Flow Feature Points, Daniel D. Doyle, Alan L. Jennings, Jonathan T. Black

AFIT Patents

A new apparatus and method for tracking a moving object with a moving camera provides a real-time, narrow field-of-view, high resolution and on target image by combining commanded motion with an optical flow algorithm for deriving motion and classifying background. Commanded motion means that movement of the pan, tilt and zoom (PTZ) unit is “commanded” by a computer, instead of being observed by the camera, so that the pan, tilt and zoom parameters are known, as opposed to having to be determined, significantly reducing the computational requirements for tracking a moving object. The present invention provides a single camera pan …

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In-Beam Γ-Ray Spectroscopy Studies Of Medium-Spin States In The Odd-Odd Nucleus 186Re, David A. Matters, F. G. Kondev, N. Aoi, Y. Ayyad, A. P. Byrne, M. P. Carpenter, J. Carroll, C. J. Chiara, P. M. Davidson, G. D. Dracoulis, Y. D. Fang, C. R. Hoffmann, R. O. Hughes, E. Ideguchi, R. V. F. Janssens, S. Kanaya, B. P. Kay, T. Kibedi, G. J. Lane, T. Lauritsen, John W. Mcclory, P. Nieminen, S. Noji, A. Odahara, H. J. Ong, A. E. Stuchbery, D. T. Tran, H. Watanabe, A. N. Wilson, Y. Yamamoto, S. Zhu Jul 2017

In-Beam Γ-Ray Spectroscopy Studies Of Medium-Spin States In The Odd-Odd Nucleus 186Re, David A. Matters, F. G. Kondev, N. Aoi, Y. Ayyad, A. P. Byrne, M. P. Carpenter, J. Carroll, C. J. Chiara, P. M. Davidson, G. D. Dracoulis, Y. D. Fang, C. R. Hoffmann, R. O. Hughes, E. Ideguchi, R. V. F. Janssens, S. Kanaya, B. P. Kay, T. Kibedi, G. J. Lane, T. Lauritsen, John W. Mcclory, P. Nieminen, S. Noji, A. Odahara, H. J. Ong, A. E. Stuchbery, D. T. Tran, H. Watanabe, A. N. Wilson, Y. Yamamoto, S. Zhu

Faculty Publications

Excited states in 186Re with spins up to J=12ℏ were investigated in two separate experiments using 186W(d,2n) reactions at beam energies of 12.5 and 14.5 MeV. Two- and threefold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed high-purity germanium detectors. Analysis of the data revealed rotational bands built on several two-quasiparticle intrinsic states, including a long-lived Kπ=(8+) isomer. Configuration assignments were supported by an analysis of in-band properties, such as |gK−gR| values. The excitation energies of the observed intrinsic states were compared with results from multi-quasiparticle blocking …

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Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks May 2017

Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks

Faculty Publications

Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined …

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Stereoscopic 3-D Presentation For Air Traffic Control Digital Radar Displays, Jason G. Russi, Brent T. Langhals, Michael E. Miller, Eric L. Heft May 2017

Stereoscopic 3-D Presentation For Air Traffic Control Digital Radar Displays, Jason G. Russi, Brent T. Langhals, Michael E. Miller, Eric L. Heft

AFIT Patents

An apparatus and method of presenting air traffic data to an air traffic controller are provided. Air traffic data including a two dimensional spatial location and altitude for a plurality of aircraft is received. A disparity value is determined based on the altitude for each aircraft of the plurality of aircraft. Left and right eye images are generated of the plurality of aircraft where at least one of the left and right eye images is based on the determined disparity value. The left and right eye images are simultaneously displayed to the air traffic controller on a display. The simultaneously …

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Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas May 2017

Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas

Faculty Publications

We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions.

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Kinetics Of High Pressure Argon-Helium Pulsed Gas Discharge, Daniel J. Emmons, David E. Weeks May 2017

Kinetics Of High Pressure Argon-Helium Pulsed Gas Discharge, Daniel J. Emmons, David E. Weeks

Faculty Publications

Simulations of a pulsed direct current discharge are performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero- and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare-gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Time dependent densities, electron temperatures, current densities, and reduced electric fields in the positive column are analyzed over a single 20 μs pulse, showing temporal agreement between the two models. Through the use of a robust reaction rate package, radiation trapping is determined to play a key role …

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Characterization Of Neutron And Proton Exposure On The Radiation Resistant Bacterium, Deinococcus Radiodurans, Ronald C. Lenker Mar 2017

Characterization Of Neutron And Proton Exposure On The Radiation Resistant Bacterium, Deinococcus Radiodurans, Ronald C. Lenker

Theses and Dissertations

Deinococcus radiodurans is a robust bacterium that is known for its extraordinary resistance to ionizing radiation. In general, many of the investigations of this bacterium's resistance have revolved around low linear energy transfer radiation, such as gamma and electron radiation. This study explored Deinococcus radiodurans's ability to survive high linear energy transfer radiation, specifically proton and neutron radiation. Deinococcus radiodurans was dehydrated to reduce the effects of low linear energy transfer radiation. The bacteria were exposed to both neutron and proton radiation of varying amounts and rehydrated. The resulting colonies were counted and compared to colonies of non-irradiated control samples …

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Cavity Perturbation Technique Of 10 Ghz Cylindrical Resonator For Modeling Rf/Ir Sensor Radomes/Windows, Marvin-Ray Arida Mar 2017

Cavity Perturbation Technique Of 10 Ghz Cylindrical Resonator For Modeling Rf/Ir Sensor Radomes/Windows, Marvin-Ray Arida

Theses and Dissertations

The dielectric properties of candidate materials for radomes or sensor windows on hypersonic vehicles, which can reach temperatures above 1,500° Celsius when traveling greater than Mach 5, are required. Although there has been recent scientific interest in the temperature dependence of the dielectric constant, little is known for temperatures near 1,500° Celsius and above. Current research utilizes large laboratory-sized furnaces to achieve these temperatures. This also requires large sample sizes, which are expensive; such expense is greatly multiplied when sweeping through hundreds of materials for research and development. In an effort to reduce these costs, this thesis modeled a 7.0 …

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Using Principal Component Analysis To Improve Fallout Characterization, Derek W. Haws Mar 2017

Using Principal Component Analysis To Improve Fallout Characterization, Derek W. Haws

Theses and Dissertations

Previous research conducted at Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) has shown a correlation between actinide location and elemental composition in fallout from historic weapons testing. Fifty spherical fallout samples were collected from near ground zero of a surface burst weapons test. The samples were mounted in an aluminum puck then ground and polished to a hemisphere exposing the central plane. Physical morphologies of the samples ranged from clear to opaque with inclusions, voids, and/or uniform characteristics. Spectroscopy data were collected using optical microscopes and scanning electron microscopy (SEM), with radioactivity recorded through …

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Rbhe Potential Energy Surface Sensitivity Study, Ethan D. Thorp Mar 2017

Rbhe Potential Energy Surface Sensitivity Study, Ethan D. Thorp

Theses and Dissertations

This paper studies how alterations of features of RbHe potential energy surfaces (PES) for a diode pumped alkali laser (DPAL) system effect the collisional cross section. The Split-Operator method is used to propagate a wave function along these PES and because they are radially coupled, the wave function can be transmitted from the starting surface to other energy surfaces. This transmittance is encoded in the correlation function. The full Hamiltonian used for propagation consists of the electronic potential, the nuclear kinetic energy, and the Coriolis coupling. The correlation function is used to generate the Scattering Matrix elements. These elements describe …

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Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross Mar 2017

Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross

Theses and Dissertations

The development of an accurate ionospheric Total Electron Content (TEC) model is of critical importance to High Frequency (HF) radio wave propagation. However, the TEC is highly variable and is continuously influenced by geomagnetic storms, extreme Ultraviolet (UV) radiation, diurnal variation, and planetary waves. The ability to capture this variability is essential to improve current TEC models. Analysis of the growing body of data involving ionospheric fluctuations and thermal tides has revealed persistent correlation between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters longwave emissions …

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Modeling The White Sands Missile Range Fast Burst Reactor Using A Discrete Ordinates Code, Pentran, Taylor R. Schulmeister Mar 2017

Modeling The White Sands Missile Range Fast Burst Reactor Using A Discrete Ordinates Code, Pentran, Taylor R. Schulmeister

Theses and Dissertations

The goal of this research was to develop and characterize a deterministic model of a fast burst reactor (FBR) using a discrete ordinates neutral particle transport code, PENTRAN. The White Sands Missile Range FBR design was chosen for this research because this FBR is important to the DoD due to its short duration, high energy neutron flux which is representative of the neutron flux output created by a nuclear weapon. One, two, and three dimensional PENTRAN models of the FBR were developed and neutron transport based eigenvalue calculations were performed. These eigenvalue calculations were conducted using two different set of …

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A Computational Study: The Effect Of Hypersonic Plasma Sheaths On Radar Cross Section For Over The Horizon Radar, Zachary W. Hoeffner Mar 2017

A Computational Study: The Effect Of Hypersonic Plasma Sheaths On Radar Cross Section For Over The Horizon Radar, Zachary W. Hoeffner

Theses and Dissertations

In this study radar cross sections were calculated for an axial symmetric 6-degree half angle blunted cone with a nose radius of 2.5 cm and length of 3.5 m including and excluding the effects of an atmospheric hypersonic plasma sheath for altitudes of 40 km, 60 km and 80 km and speeds of 5 km/s, 6 km/s and 7 km/s. LAURA, was used to determine the plasma characteristics for the hypersonic flight conditions using a 11-species 2-temperature chemical model. Runs were accomplished first with a super-catalytic surface boundary condition without a turbulence model and then for some cases with an …

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The Fresnel Zone Light Field Spectral Imager, Francis D. Hallada Mar 2017

The Fresnel Zone Light Field Spectral Imager, Francis D. Hallada

Theses and Dissertations

This thesis provides a computational model and the first experimental demonstration of a Fresnel zone light field spectral imaging (FZLFSI) system. This type of system couples an axial dispersion binary diffractive optic with light field (plenoptic) camera designs providing a snapshot spectral imaging capability. A computational model of the system was developed based on wave optics methods using Fresnel propagation. It was validated experimentally and provides excellent demonstration of system capabilities. The experimentally demonstrated system was able to synthetically refocus monochromatic images across greater than a 100nm bandwidth. Furthermore, the demonstrated system was modeled to have a full range of …

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Synthesizing Time-Evolving Partially-Coherent Schell-Model Sources, Noah R. Van Zandt, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao, Steven T. Fiorino Mar 2017

Synthesizing Time-Evolving Partially-Coherent Schell-Model Sources, Noah R. Van Zandt, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao, Steven T. Fiorino

Faculty Publications

Time-evolving simulation of sources with partial spatial and temporal coherence is sometimes instructive or necessary to explain optical coherence effects. Yet, existing time-evolving synthesis techniques often require prohibitive amounts of computer memory. This paper discusses three methods for the synthesis of continuous or pulsed time-evolving sources with nearly arbitrary spatial and temporal coherence. One method greatly reduces computer memory requirements, making this type of synthesis more practical. The utility of all three methods is demonstrated via a modified form of Young's experiment. Numerical simulation and laboratory results for time-averaged irradiance are presented and compared with theory to validate the synthesis …

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Estimation Of Turbulence From Time-Lapse Imagery, Jack E. Mccrae, Santasri Bose-Pillai, Steven T. Fiorino Feb 2017

Estimation Of Turbulence From Time-Lapse Imagery, Jack E. Mccrae, Santasri Bose-Pillai, Steven T. Fiorino

Faculty Publications

Atmospheric turbulence parameters are estimated for an imaging path based on time-lapse imaging results. Atmospheric turbulence causes frame-to-frame shifts of the entire image as well as parts of the image. The statistics of these shifts encode information about the turbulence strength (as characterized by Cn2, the refractive index structure function constant) along the optical path. The shift variance observed is simply proportional to the variance of the tilt of the optical field averaged over the area being tracked and averaged over the camera aperture. By presuming this turbulence follows the Kolmogorov spectrum, weighting functions, which relate the turbulence strength along …

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