Electromagnetics and Photonics Commons^™

Binary And Core-Shell Nanoparticle Dispersed Liquid Crystal Cells For Metamaterial Applications, George Nehmetallah, Rola Aylo, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We theoretically explored the feasibility of a tunable metamaterial using binary as well as core-shell nanoparticle dispersed liquid crystal cells in the infrared and optical regimes. Owing to the spatial variation of the permittivity of the liquid crystal host upon the application of a bias voltage, the host was decomposed into a layered medium and the effective refractive index recalculated for each layer due to the distribution of polaritonic and plasmonic nanoparticles.

The scattering, extinction, and absorption of such a nanoparticle dispersed liquid crystal cell were also found. Depending on the applied voltage bias across the liquid crystal host, the …

Single-Beam Holographic Tomography Creates Images In Three Dimensions, George Nehmetallah, Partha P. Banerjee, Nickolai Kukhtarev

Electrical and Computer Engineering Faculty Publications

In digital holography (DH), the interference between light scattered from an object and a reference wave is recorded using a CCD camera. DH has various advantages over analog holography: no film processing is needed, reconstruction is performed using numerical methods, and no further experimental setup is necessary. However, one of the disadvantages of DH is that current CCDs have a resolution of approximately 1,000 lines/mm, which is less than that of photographic film.

Anisotropic Electrical Properties Of Nanostructured Metallic Thin Films, Mo Ahoujja, Piyush Shah, Andrew Saragan, Said Elhamri, Elena A. Guliants

Electrical and Computer Engineering Faculty Publications

High surface area, porous, metallic (Ti, Cr) nanorod thin ¯lms with columnar microstructure can be deposited using conventional physical vapor deposition technique of E-beam evaporation. The technique relies on the physical vapor deposition onto a static substrate oriented in a position where °ux from the source material (Ti, Cr) arrives at oblique angle. The adatoms provides geometrical shadowing which results in growth of nanorod columns in the direction of vapor source. Deposition conditions such as angle of the incoming vapor °ux, substrate temperature, surface di®usion etc. have strong in°uence on the shape and arrangement of the columnar thin ¯lms. In …

Multi-Pose Face Recognition And Tracking System, Binu Muraleedharan Nair, Jacob Foytik, Richard Tompkins, Yakov Diskin, Theus Aspiras, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

We propose a real time system for person detection, recognition and tracking using frontal and profile faces. The system integrates face detection, face recognition and tracking techniques. The face detection algorithm uses both frontal face and profile face detectors by extracting the 'Haar' features and uses them in a cascade of boosted classifiers. The pose is determined from the face detection algorithm which uses a combination of profile and frontal face cascades and, depending on the pose, the face is compared with a particular set of faces having the same range for classification. The detected faces are recognized by projecting …

Fluorinated Templates For Energy-Related Nanomaterials And Applications, Mohammed J. Meziani, Fushen Lu, Li Cao, Christopher E. Bunker, Elena A. Guliants, Ya-Ping Sun

Electrical and Computer Engineering Faculty Publications

Fluorinated ionomer membranes, as represented by the commercially available Nafion films, are macroscopically homogeneous and optically transparent but microscopically inhomogeneous with the presence of nanoscale hydrophilic cavities. These cavities serve as nanoscale reactors for the synthesis of nanoparticles from a variety of materials. The membranes with embedded nanoscale semiconductors, still optically transparent, have been used as sheet-photocatalysts for energy conversion applications, while those with embedded reactive metals used as nano-energetic materials for hydrogen generation and beyond. This chapter provides an overview on the templated synthesis of nanomaterials in fluorinated ionomer membranes and the various energy-related applications of this unique class …

Comparison Of Turbulence-Induced Scintillations For Multi-Wavelength Laser Beacons Over Tactical (7 Km) And Long (149 Km) Atmospheric Propagation Paths, Mikhail Vorontsov, Venkata S. Rao Gudimetla, Gary W. Carhart, Thomas Weyrauch, Svetlana Lachinova, Ernst Polnau, Joseph Rierson, Leonid A. Beresnev, Jony Jiang Liu, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We report results of the experimental analysis of atmospheric effects on laser beam propagation over two distinctive propagation paths: a long-range (149 km) propagation path between Mauna Loa (Island of Hawaii) and Haleakala (Island of Maui) mountains, and a tactical-range (7 km) propagation path between the roof of the Dayton Veterans Administration Medical Center (VAMC) and the Intelligent Optics Laboratory (IOL/UD) located on the 5th floor of the University of Dayton College Park Center building. Both testbeds include three laser beacons operating at wavelengths 532 nm, 1064 nm, and 1550 nm and a set of identical optical receiver systems with …

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.

Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, Gary Cook, J. L. Barnes, S. A. Basun, Dean R. Evans, Ron F. Ziolo, Arturo Ponce, Victor Yu. Reshetnyak, Anatoliy Glushchenko, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We describe techniques to selectively harvest single ferroelectric domain nanoparticles of BaTiO3 as small as 9 nm from a plethora of nanoparticles produced by mechanical grinding. High resolution transmission electron microscopy imaging shows the unidomain atomic structure of the nanoparticles and reveals compressive and tensile surface strains which are attributed to the preservation of ferroelectric behavior in these particles.

We demonstrate the positive benefits of using harvested nanoparticles in disparate liquid crystal systems.

Characterization Of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons, Mikhail Vorontsov, Gary W. Carhart, Venkata S. Rao Gudimetla, Thomas Weyrauch, Eric Stevenson, Svetlana Lachinova, Leonid A. Beresnev, Jony Jiang Liu, Karl Rehder, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We describe preliminary results of a set of laser beam propagation experiments performed over a long (149 km) near-horizontal propagation path between Mauna Loa (Hawaii Island) and Haleakala (Island of Maui) mountains in February 2010. The distinctive feature of the experimental campaign referred to here as the Coherent Multi-Beam Atmospheric Transceiver (COMBAT) experiments is that the measurements of the atmospheric-turbulence induced laser beam intensity scintillations at the receiver telescope aperture were obtained simultaneously using three laser sources (laser beacons) with different wavelengths (λ1 = 0.53 μm, λ2 = 1.06 μm, and λ3 = 1.55 μm). The presented experimental results on …

Design Of Acousto-Optic Chaos Based Secure Free-Space Optical Communication Links, Anjan K. Ghosh, Pramode K. Verma, Samuel Cheng, Robert C. Huck, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

We discuss the design of an acousto-optic cell based free space optical communication link where the data beam is made secure through chaos encryption. Using external signal modulation of the diffracted light from a hybrid acousto-optic cell chaos (or directly via incorporation in the sound-cell driver's bias voltage) encryption of data is possible. We have shown numerically that decryption of the encoded data is possible by using an identical acousto-optic system in the receiver.

Inhibition Of Linear Absorption In Opaque Materials Using Phase-Locked Harmonic Generation, Marco Centini, Vito Roppo, Eugenio Fazio, Federico Pettazzi, Concita Sibilia, Joseph W. Haus, John V. Foreman, Neset Akozbek, Mark J. Bloemer, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We theoretically predict and experimentally demonstrate inhibition of linear absorption for phase and group velocity mismatched second- and third-harmonic generation in strongly absorbing materials, GaAs, in particular, at frequencies above the absorption edge.

A 100-fs pump pulse tuned to 1300 nm generates 650 and 435 nm second- and third-harmonic pulses that propagate across a 450−μm-thick GaAs substrate without being absorbed.

We attribute this to a phase-locking mechanism that causes the pump to trap the harmonics and to impress on them its dispersive properties.

Modeling And Characterization Of Adaptive Lanthanum-Modified Lead Zirconate Titanate (Plzt) Microlenses, Yasser A. Abdelaziez, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We report the modeling and characterization of adaptive voltage controlled electro-optic microlenses. First, we utilize finite element analysis (FEA) to simulate the induced electro-optic effect in lanthanum-modified lead zirconate titanate (PLZT). FEA simulation provides microlens parameters such as phase and focal length. A simple z-scan method is developed to fully characterize the adaptive voltage controlled linear lens. Experimental z-scan results are shown to match the theoretical predictions from FEA.

Tailoring Metallodielectric Structures For Superresolution And Superguiding Applications In The Visible And Near-Ir Ranges, Domenico De Ceglia, Maria Antonietta Vincenti, M. G. Cappeddu, Marco Centini, Neset Akozbek, Antonella D'Orazio, Joseph W. Haus, Mark J. Bloemer, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We discuss propagation effects in realistic, transparent, metallodielectric photonic band gap structures in the context of negative refraction and super-resolution in the visible and near infrared ranges. In the resonance tunneling regime, we find that for transverse-magnetic incident polarization, field localization effects contribute to a waveguiding phenomenon that makes it possible for the light to remain confined within a small fraction of a wavelength, without any transverse boundaries, due to the suppression of diffraction. This effect is related to negative refraction of the Poynting vector inside each metal layer, balanced by normal refraction inside the adjacent dielectric layer: The degree …

Examination Of Energy And Group Velocities In Positive And Negative Index Chiral Materials With And Without Dispersion, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Concepts of energy and group velocities, Poynting and propagation vectors are examined for both positive and negative index materials. Known definitions for these entities are explored in terms of the interplay of chirality and dispersion.

Analysis Of Beam Propagation In 90-Degree Holographic Recording And Readout Using Transfer Functions And Numerical 2-D-Laplace Inversion, Monish Ranjan Chatterjee, Partha P. Banerjee, George Nehmetallah

Electrical and Computer Engineering Faculty Publications

Recently, 2-D-Laplace analysis of recording and readout of edge-holograms was reported. Numerical Laplace inversion was examined for simple test cases. Inversion algorithms are applied to examine beam shaping and distortion in photovoltaic and photorefractive materials.

Study Of Soliton Stabilization In D+1 Dimensions Using Novel Analytical And Numerical Techniques, George Nehmetallah, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

In this Chapter, we provide a brief review of the underlying nonlinear Schrödinger and associated equations that model spatio-temporal propagation in one and higher dimensions in a nonlinear dispersive environment. Particular attention is given to fast adaptive numerical techniques to solve such equations, and in the presence of dispersion and nonlinearity management, saturating nonlinearity and nonparaxiality. A unique variational approach is also outlined which helps in determining the ranges of nonlinearity and dispersion parameters to ensure stable solutions of the nonlinear equations. The propagation of 3+1 dimensional spatio-temporal pulses, or optical bullets is also modeled using a fast adaptive split-step …

Atmospheric Turbulence Compensation Of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique On Amos 3.6 M Telescope, Mikhail Vorontsov, Jim F. Riker, Gary W. Carhart, Venkata S. Rao Gudimetla, Leonid A. Beresnev, Thomas Weyrauch

Electrical and Computer Engineering Faculty Publications

The Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation does not use a conventional wavefront sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in [1]. However this technique, while widely simulated and tested in the laboratory, was not yet verified in astronomical field site experiments. During the month of May 2007, a series of experiments with SPGD-AO …

Adaptive Optics Performance Over Long Horizontal Paths: Aperture Effects In Multi-Conjugate Adaptive Optical Systems, Miao Yu, Mikhail Vorontsov, Svetlana Lachinova, Jim F. Riker, Venkata S. Rao Gudimetla

Electrical and Computer Engineering Faculty Publications

We analyze various scenarios of the aperture effects in adaptive optical receiver-type systems when inhomogeneities of the wave propagation medium are distributed over long horizontal propagation path, or localized in a few thin layers remotely located from the receiver telescope pupil. Phase aberration compensation is performed using closed-loop control architectures based on phase conjugation and decoupled stochastic parallel gradient descent (DSPGD) control algorithms. Both receiver system aperture diffraction effects and the impact of wave-front corrector position on phase aberration compensation efficiency are analyzed for adaptive systems with single or multiple wave-front correctors.

Investigation Of Negative Refractive Index In Reciprocal Chiral Materials, Monish Ranjan Chatterjee, Partha P. Banerjee, Pradeep R. Anugula

Electrical and Computer Engineering Faculty Publications

It is well known that there exist both natural materials (such as milk or sugar solution) possessing chiral (or handed) properties, as well as an increasing list of man-made materials (such as sodium bromate) that exhibit chirality. One of the principal properties of chirality is that light of any arbitrary polarization, when propagating through a chiral material, splits up into two circular polarizations propagating in different directions. In the past decade or longer, researchers have investigated electromagnetic transverse (plane) wave propagation across a non-chiral/chiral interface, and determined the electromagnetic Fresnel coefficients for such propagation. Traditionally, such coefficients are derived under …

Pocket Deformable Mirror For Adaptive Optics Applications, Leonid A. Beresnev, Mikhail Vorontsov, Peter Wangsness

Electrical and Computer Engineering Faculty Publications

Adaptive/active optical elements are designed to improve optical system performance in the presence of phase aberrations. For atmospheric optics and astronomical applications, an ideal deformable mirror should have sufficient frequency bandwidth for compensation of fast changing wave front aberrations induced by either atmospheric turbulences or by turbulent air flows surrounding a flying object (air optical effects). In many applications, such as atmospheric target tracking, remote sensing from flying aircraft, boundary layer imaging, laser communication and laser beam projection over near horizontal propagation paths the phase aberration frequency bandwidth can exceed several kHz. These fast-changing aberrations are currently compensated using relatively …

Adaptive Beam Director For A Tiled Fiber Array, Mikhail Vorontsov, Jim F. Riker, Ernst Polnau, Svetlana Lachinova, Venkata S. Rao Gudimetla

Electrical and Computer Engineering Faculty Publications

We present the concept development of a novel atmospheric compensation system based on adaptive tiled fiber array architecture operating with target-in-the-loop scenarios for directed beam applications. The adaptive tiled fiber array system is integrated with adaptive beam director (ABD). Wavefront control and sensing functions are performed directly on the beam director telescope primary mirror. The beam control of the adaptive tiled fiber array aims to compensate atmospheric turbulence-induced dynamic phase aberrations and results in a corresponding brightness increase on the illuminated extended object. The system is specifically designed for tiled fiber system architectures operating in strong intensity scintillation and speckle-modulation …

Electromagnetic Propagation Prediction Inside Aircraft Cabins, Genevieve Hankins

Electrical & Computer Engineering Theses & Dissertations

Electromagnetic propagation models for signal strength prediction within aircraft cabins are essential for evaluating and designing a wireless communication system to be implemented onboard aircraft. There are many commercially available software packages for predicting wireless system performance in conventional indoor environments. It is of interest to examine the available software to determine if the aircraft's electromagnetic environment (EME) can be modeled successfully without developing an aircraft specific prediction tool. EnterprisePlanner®, a registered product of Wireless Valley Communications, Incorporated, was selected for the present effort. The performance of the prediction model was evaluated through a comparison with field measurements taken on …

Electromagnetic Wave Propagation Prediction For Wireless Networks Inside Boeing Fuselages, Mennatoallah Youssef

Electrical & Computer Engineering Theses & Dissertations

Commercial grade software is intended for electromagnetic predictions within office buildings; it was used to develop models to analyze propagation inside airplane fuselages. This study shows that Wireless XGTD and Insite software can accurately predict power propagation within airplane fuselages. Current work uses fuselage models, which contain additional internal components. A comparison was made between empty and full fuselage to examine the effects of internal components. Two propagation model types [Fast 3D and Full 3D] were also compared for accuracy to experimental study. It was concluded that completed fuselages are suggested for further simulation study as well as that the …

Signal Flow Analysis, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Signal flow graphs are a viable alternative to block diagrammatic representation of a system. What makes signal flow graphs attractive is that certain features from graph theory can be applied to the simplification and the synthesis of complex systems.

Functional Nanoparticles In Thin Films As Sensing Media, Elena A. Guliants, Ryan Schwarb, Hope Bearbower, James R. Gord, Christopher E. Bunker

Electrical and Computer Engineering Faculty Publications

The combination of unique properties offered by materials on the nanoscale with the increased role of surface chemistry in nanostructured solids makes core-shell nanoparticles extremely attractive for application to "smart" thin-film coatings. Sensing properties of nanoparticle-based thin films were studied in several systems containing organic-coated semiconductor and metallic particles. In semiconductors, the interaction of organic shell and/or thin-film "matrix" with the environment results in changes in the nanoparticle's surface states, altering the optical properties of the thin film. Measuring the electrical properties of thin films composed of metallic cores with hydrocarbon shells offers another mechanism to monitor the local environment …

Volume Holographic Recording And Readout For 90-Deg Geometry, Partha P. Banerjee, Monish Ranjan Chatterjee, Nickolai Kukhtarev, Tatiana Kukhtareva

Electrical and Computer Engineering Faculty Publications

When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type diffracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function approach based on 2-D Laplace transforms. In a second series of investigations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various dependences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the …

Volume Holographic Optical Elements, Ching-Cherng Sun, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

The final two papers are concerned with the analysis of novel holograms. Banerjee et al. investigate holographic recording and reconstruction for edge-lit holograms recorded in a 90-degree geometry. Various cases of recording and readout that incorporate propagational diffraction have been modeled. It is shown that the 90-degree geometry can result in beam shaping, as evidenced through preliminary experimental results with photorefractive lithium niobate. Nguyen et al. propose a new approach for designing computer-generated holograms. An artificial neural network is used to initiate the genetic algorithm so that the high computation cost of genetic algorithms for synthesizing holograms is significantly reduced …

An Analysis Of Electromagnetic Interference (Emi) Of Ultra Wideband(Uwb) And Ieee 802.11a Wireless Local Area Network (Wlan) Employing Orthogonal Frequency Division Multiplexing (Ofdm), Juan Lopez Jr.

Theses and Dissertations

Military communications require the rapid deployment of mobile, high-bandwidth systems. These systems must provide anytime, anywhere capabilities with minimal interference to existing military, private, and commercial communications. Ultra Wideband (UWB) technology is being advanced as the next generation radio technology and has the potential to revolutionize indoor wireless communications. The ability of UWB to mitigate multipath fading, provide high-throughput data rates (e.g., greater than 100 Mbps), provide excellent signal penetration (e.g., through walls), and low implementation costs makes it an ideal technology for a wide range of private and public sector applications. Preliminary UWB studies conducted by The Institute for …

Examination Of Focused Beam Propagation Through A Finite Non-Reciprocal Planar Chiral Slab Using Complex Fresnel Coefficients And Dual Transforms, Monish Ranjan Chatterjee, Sumit Nema, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Recently, uniform plane wave propagation across a nonchiral-chiral interface was examined via the development of appropriate Fresnel coefficients. In this extension, propagation of focused uniform and profiled beams through a finite, planar nonreciprocal chiral slab is investigated using complex Fresnel coefficients via angular plane wave decomposition and dual transforms.