Electrical and Electronics Commons^™

Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell

Electrical and Computer Engineering Faculty Publications

The ring synthetic discriminant function (RSDF) filter for rotation-invariant response is discussed for pattern recognition. This method uses one half of a slice of the Fourier transform of the object to generate the transfer function of the filter. This is accomplished by rotating the one half of a slice in the Fourier domain through 2π rad about the zero-frequency point of the Fourier plane. This filter has the advantage of always matching at least one half of a slice of the Fourier transform of any rotation of the image. An analytical discussion of the filter construction and correlation results are …

Characterization Of Poly-Si Thin Films Deposited By Magnetron Sputtering Onto Ni Prelayers, Elena A. Guliants, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

A method of producing a polycrystalline silicon thin film on a foreign substrate without subsequent annealing has been developed. Thermally evaporated 5–100 nm thick Nifilms served as prelayers for magnetron sputtered Si thin films. A continuous film was obtained as a result of metal induced growth of polysilicon during low temperature (below 600 °C) deposition. The film uniformity is promising for large area device applications. The influence of the Ni prelayer thickness on the grain size of thus obtained films was investigated. Atomic force microscopy and cross-sectional scanning electron microscopy studies revealed features in the 150–600 nm size range while …

Nonlinear Self-Organization In Photorefractive Materials, Partha P. Banerjee, Nickolai Kukhtarev, John O. Dimmock

Electrical and Computer Engineering Faculty Publications

This chapter discusses self-organization and its effects in optics. One of the most exciting and potentially useful areas of current research in optics involves the understanding and exploitation of self-organization in nonlinear optical systems. This self-organization may sometimes lead to the evolution of complex spatial patterns that can be regarded as the nonlinear eigenmodes of the system. Generation of these patterns is characteristically marked by the presence of intensity thresholds. In a nonlinear system with complicated temporal dynamics, it turns out that one cannot retain purity in spatial dimensionality. It is therefore equally important to investigate the dynamics of the …

Optimisation Of Transverse Arc Array Laser, Albert Kok Foo Ng

Student Works (2000-2009)

A novel discharge scheme is proposed for the pumping of short wavelen,gth lasers. This scheme had been tested to produce fast current pulse and a 5 kA current in 60 nsec is obtained. Lasing action has been observed by using nitrogen gas. The laser line is 337 nm from the strong transitions of nitrogen molecules. The new discharge scheme is based on the concept of an arc array amplifier. It essentially consists of 48 pairs of electrodes which are lined up to form an array of arc discharge. Its electrical circuitry allows each pair of the electrodes to be decoupled …

Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon

Electrical and Computer Engineering Faculty Publications

This guest editorial provides an overview of the topical area and an introduction to the articles featured in the special section.

Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao

Electrical and Computer Engineering Faculty Publications

It is commonly known that the spatial profiles of the diffracted light beams during Bragg acousto-optic interaction are distorted due to the Bragg angle selection mechanism. All the conventional studies on this effect use the paraxial approximation. But this approximation should be amended when the incident angle of the light is large enough that the diffracted light waves do not propagate closely along the optic axis of the acousto-optic diffraction system. By using a spatial Fourier transform approach, we rigorously study the light beam profile deformation effect of the diffracted light during the Bragg acousto-optic interaction beyond the paraxial approximation. …

Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan

Electrical and Computer Engineering Faculty Publications

A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for …

Differential Reflection Phase Shift Under Conditions Of Attenuated Internal Reflection, R. M.A. Azzam

Electrical Engineering Faculty Publications

The angle-of-incidence dependence of the differential reflection phase shift Δ between p and s polarizations is considered a function of the real and imaginary parts of the relative complex dielectric function ε of an interface in the domain of fractional optical constants, i.e., under conditions of internal reflection. The constraint on complex ε such that oscillatory and monotonic angular responses are obtained is determined. A sensitive and stable technique, which is based on attenuated internal reflection ellipsometry between the Brewster angle and the critical angle, is proposed for measuring small induced absorption (ε_i∼10⁻⁵) in the medium …

Self-Enhancement Of Dynamic Gratings In Photogalvanic Crystals, Nickolai Kukhtarev, Sergei F. Lyuksyutov, Preben Buchhave, Tatiana Kukhtareva, K. Sayano, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We have developed a compact closed-form solution of the band transport model for high-contrast gratings in photogalvanic crystals. Our solution predicts the effect of the photoconductivity and the electric field grating enhancement due to the photogalvanic effect. We predict a pronounced dependence of the steady-state photogalvanic current on the contrast of the interference pattern and an increase of holographic storage time due to the enhancement of the photoconductivity grating contrast. In the high contrast limit and a large photogalvanic effect the refractive index grating will be shifted from the position of the intensity modulation pattern, contrary to the usually adopted …

Experimental Investigations Of Wavelength And Angular Errors In Holographic Gratings With Non-Bragg-Matched Read Beams, Monish Ranjan Chatterjee, Vivek Ray

Electrical and Computer Engineering Faculty Publications

Perfect Bragg matching is generally desirable for accurate optical interconnections with holographic gratings. In reality, however, gratings may be illuminated by READ beams with non-Bragg-matched angles, or wavelengths, or both. In such cases, the scattered beams are generally misdirected, and may suffer loss of efficiency and possibly more serious errors such as crosstalk noise or missed connections. A conventional wave-vector triad method of analyzing the scattered beam errors leads readily to near-Bragg estimates of the output angular misalignment. However, the READ wave-vector triads appear to indicate a possible wavelength shift in the output beam even with a Bragg-matched READ wavelength, …

Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka

Electrical and Computer Engineering Faculty Publications

In many practical situations, it is important to determine and measure the attitude of a particular vehicle, such as a ship, an airplane, a piece of mechanical equipment such as a, crane lifter, or a spacecraft. For this reason, many attitude sensors have been developed with advanced computer and semiconductor technologies. This section first introduces the various attitude sensors with an explanation of their operating principles and then presents several methodologies for attitude measurement and determination, including ships and crane lifters, aircraft, and spacecraft applications.

Joint Map Registration And High Resolution Image Estimation Using A Sequence Of Undersampled Images, Russell C. Hardie, Kenneth J. Barnard, Ernest E. Armstrong

Electrical and Computer Engineering Faculty Publications

n many imaging systems, the detector array is not sufficiently dense to adequately sample the scene with the desired field of view. This is particularly true for many infrared focal plane arrays. Thus, the resulting images may be severely aliased. This paper examines a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled frames. Several approaches to this problem have been investigated previously. However, in this paper a maximum a posteriori (MAP) framework for jointly estimating image registration parameters and the high-resolution image is presented. Several previous approaches have relied on knowing the registration parameters …

Translation Of 'Profiles In Faith', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

Sarat Chandra Chatterjee (1876-1938) may be considered one of the three most significant figures of the literary component of the Bengal Renaissance, the other two being Bankim Chandra Chatterjee (1838-1894) and Rabindranath Tagore (1861-1941). As much as Bankim Chandra is identified with the new age in the Bengali novel, and the development of serious vernacular journalism, and Rabindranath with modern/classical movements in Bengali poetry and music, along with novel ideas in methods of education and teaching, Sarat Chandra, as a novelist and storyteller, perfected the art of narration and critical analyses of a variety of contemporaneous social and political issues, …

Maximum Likelihood Estimation Of Wave Front Slopes Using A Hartmann-Type Sensor, Scott A. Sallberg

Theses and Dissertations

Current methods for estimating the wave front slope at the pupil of a telescope equipped with a Hartmann-type wave front sensor (H-WFS) are based on a simple centroid calculation of the intensity distributions (spots) recorded in each subaperture of the H-WFS. The centroid method does not include any knowledge concerning correlation properties of the slopes over the subapertures or the amount of light collected by the telescope and diverted to the H-WFS for wave front reconstruction purposes. This thesis devises a maximum likelihood (ML) estimation of the spot centroids by incorporating statistical knowledge of the spot shifts. The light level …

Effects Of Neutron Radiation On Resonant Cavity Light-Emitting Diodes, Daniel S. Hinkel

Theses and Dissertations

Resonant Cavity Light Emitting Diodes (RCLEDs) were irradiated in Ohio State University's nuclear reactor to determine the effects of Neutron displacement damage. The RCLEDs were characterized both before and after irradiation by their current versus voltage curves (I-V curves) and external light power versus current curves (L-I curves). The I-V curves showed an increase in the "knee voltage" at a neutron fluence of 1.45x10¹⁷ neutrons/cm2. Logarithmic decreases in external light power and differential quantum efficiency were observed. Significant decreases in external light power were observed at neutron fluences greater than 5.1x10¹³ neutrons/cm². Equations were developed to …

Broadband Dynamic, Holographically Self-Recorded, And Static Hexagonal Scattering Patterns In Photorefractive Knbo3:Fe, Nickolai Kukhtarev, Tatiana V. Kukhtareva, John Caulfield, Partha P. Banerjee, Hsueh-Ling Yu, Lambertus Hesselink

Electrical and Computer Engineering Faculty Publications

We have observed and explained three types of hexagon pattern formation in photo refractive crystal KNb03:Fe. These are:

• Dynamic (laser induced)
• Semipermanent (holographically stored)
• Permanent (induced by a static domain grid) over a wide wavelength range

Transient Wave Mixing And Recording Kinetics In Photorefractive Barium Titanate: A Nonlinear Coupled Mode Approach, Partha P. Banerjee, John M. Jarem

Electrical and Computer Engineering Faculty Publications

By using rigorous coupled-wave diffraction theory along with a time-dependent nonlinear formulation, we analyze two- and multiplewave coupling and the grating kinetics in BaTi03 with different boundary interfaces. Efffects of electrostatic and optical anisotropy have been included in the analysis. Significant mode conversion to higher orders is observed only when the boundary interfaces are highly mismatched.

Guest Editorial: Special Section On Photorefractive Nonlinear Optics, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Hand in hand with experimental work in photorefractives, there is a lot of activity in modeling photorefractive materials and experimental observations in the open literature. This special section contains a paper by Banerjee and Jarem, who use a rigorous coupled wave theory to analyze two- and multiple-wave mixing photorefractive barium titanate, modeled through the Kukhtarev equations.

Single-Layer-Coated Surfaces With Linearized Reflectance Versus Angle Of Incidence: Application To Passive And Active Silicon Rotation Sensors, R. M.A. Azzam, M. M. K. Howlader, T. Y. Georgiou

Electrical Engineering Faculty Publications

A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear reflectanceversus- angle-of-incidence response over a certain range of angles. Linearization at and near normal incidence is a special case that leads to a maximally flat response for p-polarized, s-polarized, or unpolarized light. For midrange and high-range linearization with moderate and high slopes, respectively, the best results are obtained when the incident light is s polarized. Application to a Si substrate that is coated with a SiO₂ film leads to novel passive and active reflection rotation sensors. Experimental results and an error analysis …

Flow Visualization Of A Turbulent Shear Flow Using An Optical Wavefront Sensor, Daniel W. Jewell

Theses and Dissertations

The research reported here investigated the use of a shearing interferometer (SI) wavefront sensor to determine the effects of shear-layer turbulence on an optical wavefront. A collimated helium-neon laser beam was propagated through a plane shear-layer produced by mixing helium and nitrogen at different velocities. Since the gases have different indices of refraction, the optical wavefront was distorted by different amounts by each gas. The SI measured the wavefront slope across the sampled area of the wavefront. The shear-layer was viewed from two orthogonal directions. This document contains shadow graphs, interference patterns imaged by each of the SI's six cameras, …

Direct Relation Between Fresnel's Interface Reflection Coefficients For The Parallel And Perpendicular Polarizations: Erratum 2, R. M.A. Azzam

Electrical Engineering Faculty Publications

The record is set straight concerning two equations that determine the reflection phase shifts at a single interface from the intensity reflectances forp- and s-polarized light at one angle of incidence. These equations appeared previously in this journal [J. Opt. Soc. Am. 69, 1007 (1979); erratum, J. Opt. Soc. Am. 70, 261 (1980)].

Optical Wavelet Transform For Fingerprint Identification, Robert P. Macdonald

Theses and Dissertations

The Federal Bureau of Investigation FBI has recently sanctioned a wavelet fingerprint image compression algorithm developed for reducing storage requirements of digitized fingerprints. This research implements an optical wavelet transform of a fingerprint image, as the first step in an optical fingerprint identification process. Wavelet filters are created from computer generated holograms of biorthogonal wavelets, the same wavelets implemented in the FBI algorithm. Using a detour phase holographic technique, a complex binary filter mask is created with both symmetry and linear phase. The wavelet transform is implemented with continuous shift using an optical correlation between binarized fingerprints written on a …

System Design Analysis Of A Lightweight Laser Satellite Terminal, Brian C. Page

Theses and Dissertations

This study investigated the technological feasibility of a man- portable satellite laser communications system. Areas of interest were an end- to-end system analysis on the communications link evaluation of atmospheric effects and evaluation of semi-conductor lasers as the laser source. A literature search revealed that satellite laser communication research is primarily directed at inter-satellite links. There have been some proposed systems for space-to-ground laser communications systems, but they all utilize large fixed ground stations. The focus of this research effort is directed at a small man-portable ground station capitalizing on recent advances in semiconductor laser devices. Baseline satellite communication systems …

Electronic Simulation Of The Temporal Characteristics Of Photon Memory Echoes And Some Related Applications, Yuwen Kuo, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

The characteristics of nonlinear photon memory echoes are investigated by means of SPICE simulations using equivalent resonator ensembles. By developing implicit nonlinear circuit models in the memory echo domain, the triple product formalism of electronic holography, involving correlation and convolution, is tested for the storage and recall of arbitrary signals and/or data bit streams in both time-inverted and nontime-inverted modes. Furthermore, a few specific optical data processing applications are also simulated in which the mixed binary multiplication of two or more binary bit streams is achieved.

Higher order products, optical pattern recognition, and other possible applications are also discussed. It …

Absorption Imaging Studies On Intrinsic Gaas, John Samuel Kenney

Electrical & Computer Engineering Theses & Dissertations

A diagnostic technique has been developed which allows recording of the temporal and spatial development of electric field structures in GaAs photoconductive switches. The optical method is based on the Franz-Keldysh effect. Measurements were performed with a Nd:YAG activation laser and a GaAs laser diode as the probe laser. At low applied voltages a 100 atm wide region of high electric field is seen at the cathode only. With increasing voltage strong domain like structures emerge at the anode also. A calibration measurement shows that the electric fields in these domains are well above 50 kV/cm. At a threshold voltage, …

Study Of Single-Fiber Fiber Optic Lever Microphone, Trung Duc Nguyen

Electrical & Computer Engineering Theses & Dissertations

Fiber optic sensors are widely used in today's technological applications, providing many advantages that conventional sensors lack. In particular, there is a demand in hypersonic applications to develop microphones to measure acoustic pressure that performs in high temperature and noisy surroundings. This thesis analyzes fiber optic lever microphones (FOLM), since they perform at high temperatures. An FOLM system is an intensity modulated sensor, which is simple to implement and is small in size. Two models of the FOLM have been fabricated and calibrated. The first model uses a seven-element fiber array while the second uses a single-fiber to transmit and …

Photopolarimeter Based On Planar Grating Diffraction, R. M.A. Azzam, K. A. Giardina

Electrical Engineering Faculty Publications

A division-of-amplitude photopolarimeter (DOAP) is described that employs a diffraction grating in the conventional spectrometer orientation with the grating grooves normal to the plane of incidence. Four coplanar diffracted orders are used for polarimetric analysis to determine all four Stokes parameters of incident light simultaneously and virtually instantaneously (with the speed being determined solely by the photodetectors and their associated electronics); a fifth order is used for alignment by autocollimation or by use of a position-sensing quadrant detector. To sensitize the instrument for the +45° and -45° azimuths of incident linearly polarized light and for the handedness of incident circular …

Self-Referenced Speckle Holography (Srsh) Image Reconstruction Performance, John R. Devey

Theses and Dissertations

The Speckle Holography technique uses a series of short exposure images and associated wave front sensor measurements to reconstruct astronomical images. The reconstruction technique effectively boosts the amplitude of high spatial frequencies to allow for finer resolution of astronomical objects. A simulation package that calculates the optical transfer function (OTF) of a telescopic system was previously developed for the Phillips Laboratory. This software was modified slightly to provide the Speckle Holography system transfer function (STF) for a telescopic system under varying seeing conditions.

Remote Sensing Of Turbulence And Transverse Atmospheric Wind Profiles Using Optical Reference Sources, Steven C. Koeffler

Theses and Dissertations

This thesis examines a remote sensing technique for measuring the atmospheric structure constant and the transverse atmospheric wind velocity as a function of altitude by performing temporal and spatial correlations of band pass filtered wave front slope sensor measurements. Two point sources are used to illuminate two pairs-of cc>-located wave front slope sensors. The sources and sensors are arranged to give rise to crossed optical paths. For each pair of wave front slope sensors, the output of the larger sensor is subtracted from the output of the smaller sensor. This band pass filters the smaller sensor's output. The filtered …

Optical Haar Wavelet Transforms Using Computer Generated Holography, Peter G. Block

Theses and Dissertations

This research introduces an optical implementation of the continuous wavelet transform to filter images. The wavelet transform is modeled as a correlation process and is implemented with a Vander Lugt correlator. The orthonormal basis set used is composed of two one-dimensional Haar functions and a two-dimensional Haar function. Each wavelet, as well as its first two dyadic scalings, is implemented with computer generated holography. The Interferogram method, which represents a function only in terms of its phase, is used to encode the wavelet functions. The results are imaged onto a CCD array and captured using a framegrabber. The optical results …