Optics Commons^™

Construction And Improvement Of A Scheffler Reflector And Thermal Storage Device, Jason Rapp

Physics

We constructed and successfully tested a 2 m2 parabolic dish solar concentrator (Scheffler Concentrator) to focus sunlight onto a stationary target. Present efforts are to decrease the construction complexity and cost of the concentrator. In order to store solar heat, we also constructed and are testing a thermal storage device made of sand (for thermal mass), and pumice (for insulation). Preliminary tests indicate thermal retention times of many hours. Present efforts are to increase accessible power, and structural integrity.

Development Of Acrylamide Based Photopolymer For Full Colour Display Holography, Chakrapani Meka

Doctoral

Holography is a firmly established discipline that can be used as a tool for scientific and engineering studies and as a display medium as well. Until now both silver halide photographic emulsions (SHPE) and dichromated gelatine (DCG) have been the most common materials used for high efficiency full colour reflection hologram recording. However, these materials require wet chemical processing for developing the holograms which is laborious and costly from the point of view of commercial applications. Self-developing photopolymers such as acrylamide based photopolymer (ABP) which do not require development are the ideal choice for real-time recording and reconstruction of holograms. …

Characterization Of Pollen Particles Using Lidar, Leda Sox

Graduate Student Posters

We have observed pollen in the local troposphere using the depolarization capabilities of a LIDAR (Light Detection and Ranging) system. The polarization characteristics of the received LIDAR signal, along with supplemental pollen forecast data, allowed me to characterize the shape of the pollen particles.

Laser Demonstration And Performance Characterization Of An Optically Pumped Alkali Laser System, Clifford V. Sulham

Theses and Dissertations

Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that will not suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL-type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795 nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm². Linear scaling as high as …

Transmission Of P- And S-Polarized Light Through A Prism And The Condition Of Minimum Deviation, R. M.A. Azzam, Ryan M. Adams

Electrical Engineering Faculty Publications

The condition of minimum deviation (MD) by a transparent optically isotropic prism is re-derived, and expressions for the intensity transmittances Tp(θ) and Ts(θ) of an uncoated prism of refractive index n and prism angle α for incident p- ands-polarized light and their derivatives with respect to the internal angle of refraction θ are obtained. When the MD condition(θ=α/2) is satisfied, Ts is maximum and Tp is maximum or minimum. The transmission ellipsometric parametersψt,Δt of a symmetrically coated prism are also shown to be locally stationary with respect to θ at θ=α/2 . The constraint on (n,α) for …

Thin Film Optical Filter Fabrication And Characterization, Adam G. Hammouda, David P. Shelton

Undergraduate Research Opportunities Program (UROP)

Thin film coatings have a large number of applications. For example, one can eliminate unwanted reflection on a photographic lens or unwanted wavelengths of light in optics experimentation. The fabrication and characterization of films whose refractive indices can be arbitrarily modulated (‘Rugate Filters’) is an ongoing exploration in materials science1,2. Therefore, calibrating a process which can manufacture such films is a relevant pursuit in forwarding such explorations. Reactive magnetron sputter deposition is a commonly used technique for the productions of thin films3,4. This technique steadily flows reactive gas (RG) into a vacuum chamber in which an electric field has been …

Heralded Single-Photon Partial Coherence, P. Ben Dixon, Gregory A. Howland, Mehul Malik, David J. Starling, R. W. Boyd, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We study transverse spatial coherence of approximately localized single-photon states. We demonstrate nonlocal control over single-photon spatial coherence via projective measurements of an entangled twin and provide a theoretical interpretation from quantum coherence theory. Our results show that the spatial coherence of a single-photon state behaves similarly to that of a classical optical field, although the coincidence measurement adds a degree of freedom.

Performance Measures In Acousto-Optic Chaotic Signal Encryption System Subject To Parametric Variations And Additive Noise, Monish Ranjan Chatterjee, Anjan K. Ghosh, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

Signal encryption and recovery using chaotic optical waves has been a subject of active research in the past 10 years. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption using a low-amplitude sinusoidal signal applied via the bias input of the sound cell driver.

Subsequent recovery of the message signal was carried out via a heterodyne strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell. The simulation results, though encouraging, were limited to relatively …

Consideration Of Dispersion And Group Velocity Dispersion In The Determination Of Velocities Of Electromagnetic Propagation, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Electromagnetic (EM) propagation velocities play an important role in the determination of power and energy flow in materials and interfaces. It is well known that group and phase velocities need to be in opposition in order to achieve negative refractive index.

Recently, we have shown that considerable differences may exist in phase, group and signal/energy velocities for normal and anomalous dispersion, especially near dielectric resonances. This paper examines the phase and group velocities in the presence of normal and anomalous dispersion, and group velocity dispersion (GVD), which requires introduction of the second order coefficient in the permittivity and permeability models.

Characterization Of Optically Stimulated Luminescent Detectors In Photon & Proton Beams For Use In Anthropomorphic Phantoms, James R. Kerns

Dissertations and Theses (Open Access)

This study investigated characteristics of optically stimulated luminescent detectors (OSLDs) in protons, allowing comparison to thermoluminescent detectors, and to be implemented into the Radiological Physics Center’s (RPC) remote audit quality assurance program for protons, and for remote anthropomorphic phantom irradiations. The OSLDs used were aluminum oxide (Al2O3:C) nanoDots from Landauer, Inc. (Glenwood, Ill.) measuring 10x10x2 mm3. A square, 20(L)x20(W)x0.5(H) cm3 piece of solid water was fabricated with pockets to allow OSLDs and TLDs to be irradiated simultaneously and perpendicular to the beam. Irradiations were performed at 5cm depth in photons, and in the center of a 10 cm SOBP in …

Simultaneous Higher Harmonic Detection And Extraction Of Information From Oxygen Spectra, Karan Dineshchandra Mohan

Electrical & Computer Engineering Theses & Dissertations

Wavelength Modulation Spectroscopy (WMS) is a highly sensitive technique that utilizes synchronous detection at the N-th harmonics of a modulating frequency, by modulating the laser beam used to probe a gaseous species. The advantage of this technique lies in the greater effective signal-to-noise ratio one obtains as a direct consequence of the larger amount of structure present in the higher harmonics, and thus a greater amount of information that can be obtained from that structure. We present the development of a novel technique where data at multiple harmonics is obtained simultaneously, rather than sequentially. This removes the susceptibility of the …

Electronic Structure Of Lithium Tetraborate, David J. Wooten

Theses and Dissertations

Due to interest as neutron detection material, an investigation of Li₂B₄O₇(110) and Li₂B₄O₇(100) was undertaken, utilizing photoemission and inverse photoemission spectroscopic techniques. The measured band gap depended on crystallographic direction with the band gaps ranging from 8.9±0.5 eV to 10.1±0.5 eV. The measurement yielded a density of states that qualitatively agreed with the theoretical results from model bulk band structure calculations for Li₂B₄O₇; albeit with a larger band gap than predicted, but consistent with the known deficiencies of LDA and DFT calculations. …

Upgrade To The Pierre Auger Cosmic Ray Observatory's Lidar System, Emily B. Petermann

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The Pierre Auger Cosmic Ray Observatory currently operates four elastic lidar systems in order to characterize the atmospheric aerosol content above the observatory. The atmospheric information gained by the lidar system is then used in the calibration of the observatory’s four fluorescence detectors. Currently the four lidars in operation are unable to accurately determine the aerosol content below a distance of 1 km. A project is currently underway to upgrade the current lidar system by adding an additional detector to each of the existing lidar systems. The considered designs for this upgrade and the initial results from the upgrade prototype …

Difference Between The Second-Brewster And Pseudo-Brewster Angles When Polarized Light Is Reflected At A Dielectric–Conductor Interface, A. Alsamman, R. M.A. Azzam

Electrical Engineering Faculty Publications

For a given pseudo-Brewster angle ϕpB of minimum reflectance ∣∣rp∣∣ of p-polarized light at a dielectric-conductor interface, the second-Brewster angle ϕ2B of minimum reflectance ratio |ρ|=∣∣rp∣∣/|rs| of the p and s polarizations is determined for all possible values of the complex relative dielectric function ϵ that lead to the same ϕpB . The difference ϕ2B−ϕpB is considered as a function of ϕpB and θ=arg(ϵ) . For any given ϕpB , the difference ϕ2B−ϕpB=0 atθ=0(ϵr>0,ϵi=0) increases monotonically as a function of θ and reaches maximum value {ϕ2B−ϕpB}max in the limit as θ→180° (ϵr<0,ϵi=0) . This maximum difference {ϕ2B−ϕpB}max has an upper limit of 15.701° whenϕpB=28.195° .

Nonlinear Photoacoustics For Measuring The Nonlinear Optical Absorption Coefficient, Chandra S. Yelleswarapu, Sri-Rajasekhar Kothapalli

Physics Faculty Publications

We report a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. The sample is scanned through the focused laser beam and the generated photoacoustic signal is recorded using a 10 MHz focused ultrasound transducer. Since the signal strength is directly proportional to the optical absorption, PAZ-scan displays nonlinear behavior depicting the nonlinear optical absorption of the material. Among many advantages, our experiments on mouse blood show that PAZ-scan can potentially be used as a standard technique to calibrate contrast agents used in theranostics in general and …

Numerical Investigation Of Statistical Turbulence Effects On Beam Propagation Through 2-D Shear Mixing Layer, James C. Bowers

Theses and Dissertations

A methodology is developed for determining the validity of making a statistical turbulent approach using Kolmogorov theory to an aero-optical turbulent ow. Kolmogorov theory provides a stochastic method that has a greatly simplified and robust method for calculating atmospheric turbulence effects on optical beam propagation, which could simplify similar approaches to chaotic aero-optical flows. A 2-D laminar Navier-Stokes CFD Solver (AVUS) is run over a splitter plate type geometry to create an aero-optical like shear mixing layer turbulence field. A Matlab algorithm is developed to import the flow data and calculates the structure functions, structure constant, and Fried Parameter ( …

Monocular Passive Ranging By An Optical System With Band Pass Filtering, Joel R. Anderson

Theses and Dissertations

An instrument for monocular passive ranging based on atmospheric oxygen absorption near 762 nm has been designed, built and deployed to track emissive targets, including the plumes from jet engines or rockets. An intensified CCD array is coupled to variable band pass liquid crystal display filter and 3.5 – 8.8 degree field of view optics to observe the target. By recording sequential images at 7 Hz in three 6 nm width bands, the transmittance of the R-branch of the O₂ (X-b) (0,0) band is determined. A metric curve for determining range from transmittance is developed using the HITRAN spectral …

Optical And Electrical Characterization Of Bulk Grown Indium-Gallium-Arsenide Alloys, Austin C. Bergstrom

Theses and Dissertations

Advances in crystal growth techniques have allowed increased quality in growth of bulk ternary In_xGa_1-xAs. Here, the optical and electrical properties of samples grown through the vertical Bridgman (or multi-component zone melting growth) method have been investigated through photoluminescence spectroscopy and Hall effect measurements. Indium mole fractions varied from 0.75 for 1. Hall effect measurements at temperatures ranging from 10 to 300 K revealed moderate n-type doping with carrier concentrations ranging from 1.5 to 9.6×10¹⁶ cm^-3 at 10 to 15 K. Carriers from deep donor levels became appreciable between 50 and 100 K. Hall …

Rubidium Recycling In A High Intensity Short Duration Pulsed Alkali Laser, Wooddy S. Miller

Theses and Dissertations

Laser induced fluorescence was used to study how pump pulse duration and alkali recycle time effects maximum power output in a Diode Pumped Alkali Laser (DPAL) system. A high intensity short pulsed pump source was used to excited rubidium atoms inside a DPAL-type laser. The maximum output power of the laser showed a strong dependence upon the temporal width of the pump pulse in addition to the input pump intensity. A linear relationship was observed between the maximum output power and the pulse width due to the effective lifetime of the excited state, defined as the time it takes for …

Afm-Patterned 2-D Thin-Film Photonic Crystal Analyzed By Complete Angle Scatter, Nicholas C. Herr

Theses and Dissertations

The purpose of this research was to use an atomic force microscope (AFM) to generate a 2-D square array of sub-wavelength surface features from a single material over a region large enough to permit optical characterization. This work is an extension of previous AFIT nano-patterning work and is in response to the small subunit sizes demanded for the production of optical metamaterials and photonic crystals. A diamond nano-indentation AFM probe was used to produce a 325-μm by 200-μm array of indentations in a 120-nm thick polystyrene film deposited on silicon. Indentation spacing of 400 nm produced well-defined surface features with …

Thermal Neutron Point Source Imaging Using A Rotating Modulation Collimator (Rmc), Nathan O. Boyce

Theses and Dissertations

This thesis demonstrates a previously untested capability of the Rotating Modulation Collimator (RMC) to image a point-like neutron source. The encouraging results, achieved using low-energy neutrons, provide motivation for further refinement and continued research with higher-energy neutrons. The detector and the masks on an existing RMC imaging system were exchanged to function with neutrons. The source in this research produced a poly-energetic spectrum of neutrons through the reaction. The source of alpha particles was a 72.7 mCi ²³⁹Pu source. The RMC detector was located 250 cm from the bare source and operated for three hours to generate a modulation …

Digital Delay Device, Guna Seetharaman, Paul E. Kladitis

AFIT Patents

A digitally controlled optical delay apparatus providing optical signal delays electrically selectable in the picosecond to nanosecond range by way of selectable signal path lengths. Path lengths are incremented in physical length and path delay time according to digital ratios. The delay element includes micro-miniature path changing mirrors controlled in path length selecting positioning by input signals of logic level magnitude. Fiber optic coupling of signals to and from the delay element and a combination of fixed position and movable mirror included optical signal path lengths are included.

Interferometric Weak Value Deflections: Quantum And Classical Treatments, John C. Howell, David J. Starling, P. Ben Dixon, Praveen K. Vudyasetu, Andrew N. Jordan

Mathematics, Physics, and Computer Science Faculty Articles and Research

We derive the weak value deflection given in an article by Dixon et al. [P. B. Dixon et al. Phys. Rev. Lett. 102 173601 (2009)] both quantum mechanically and classically, including diffraction effects. This article is meant to cover some of the mathematical details omitted in that article owing to space constraints.

Liquid Filled Microstructured Optical Fiber For X-Ray Detection, S. L. Dehaven, S. Albin, W. C. Kelliher

Electrical & Computer Engineering Faculty Publications

A liquid filled microstructured optical fiber (MOF) is used to detect x-rays. Numerical analysis and experimental observation leads to geometric fiber optics theory for MOF photon transmission. A model using this theory relates the quantity and energy of absorbed x-ray photons to transmitted MOF generated photons. Experimental measurements of MOF photon quantities compared with calculated values show good qualitative agreement. The difference between the calculated and measured values is discussed. 2010 Optical Society of America

Response-Calibration Techniques For Antenna-Coupled Infrared Sensors, Peter Krenz

Electronic Theses and Dissertations

Infrared antennas are employed in sensing applications requiring specific spectral, polarization, and directional properties. Because of their inherently small dimensions, there is significant interaction, both thermal and electromagnetic, between the antenna, the antenna-coupled sensor, and the low-frequency readout structures necessary for signal extraction at the baseband modulation frequency. Validation of design models against measurements requires separation of these effects so that the response of the antenna-coupled sensor alone can be measured in a calibrated manner. Such validations will allow confident extension of design techniques to more complex infrared-antenna configurations. Two general techniques are explored to accomplish this goal. The extraneous …

Fast-Response Liquid Crystal Displays, Meizi Jiao

Electronic Theses and Dissertations

After about five decades of extensive material research and device development, followed by massive investment in manufacturing technology, thin-film-transistor liquid-crystaldisplay (TFT-LCD) has finally become the dominant flat panel display technology. Nowadays, LCD performances, such as viewing angle, contrast ratio, and resolution, have reached acceptable levels. The remaining major technical challenges are response time, light efficiency, and sunlight readability. Fast response time is desired to reduce motion blur and to enable field sequential color displays using red (R), green (G), and blue (B) LEDs (light emitting diodes) without noticeable color breakup. Sequential RGB colors would eliminate the commonly used spatial color …

Demonstration Of A Neutral Atom Controlled-Not Quantum Gate, L. Isenhower, E. Urban, X. L. Zhang, A. T. Gill, T. Henage, Todd A. Johnson, T. G. Walker, M. Saffman

Physics Faculty Publications

We present the first demonstration of a CNOT gate between two individually addressed neutral atoms. Our implementation of the CNOT uses Rydberg blockade interactions between neutral atoms held in optical traps separated by >8  μm. Using two different gate protocols we measure CNOT fidelities of F=0.73 and 0.72 based on truth table probabilities. The gate was used to generate Bell states with fidelity F=0.48±0.06. After correcting for atom loss we obtain an a posteriori entanglement fidelity of F=0.58.

The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman

Electronic Theses and Dissertations

This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in …

Long Cavity Quantum Dot Laser Diode And Monolithic Passively Mode-Locked Operation, K Shavitranuruk

Electronic Theses and Dissertations

Advantage of the single QD active layer is its potential for very low threshold current density, which in turn can produce low internal optical loss. The low threshold current density and low internal loss thus enable a significant increase in laser diode cavity length. Because of the importance of the threshold current density in heatsinking, future technology of broad-area monolithic laser diodes can be implemented. The dissertation describes the development and the unique characteristics of single QD active layer laser with long cavity. The data are presented on single layer QD laser diodes that reach threshold current densities values of …

Nonlinear Fiber Lasers Using Bismuth Based Erbium Doped Fiber Amplifier., Sharifeh Shahi

Student Works (2010-2019)

A thorough study on Bismuth-based Erbium-doped fiber (Bi-EDF) is presented for wide-band amplifiers and multi-wavelength fiber laser applications. This fiber allows high Erbium ions concentration to be doped without a significant concentration quenching effect. The high refractive index characteristic in the Bi-EDF has broadened the emission spectrum of Erbium ions to achieve a broader gain spectrum up to extended L-band region compared to normal silica-based Erbium-doped fiber (EDF). The Bi-EDFA performances have been investigated in terms of power conversion efficiency (PCE), quantum conversion efficiency (QCE), gain and noise figure. The highest QCE and PCE for a 215 cm long of …