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Ultrashort Pulse Production In Synchronously Pumped Mode-Locked Dye Laser Systems, Duncan Leo Macfarlane

Dissertations and Theses

The concern of this dissertation is the understanding and improvement of a class of lasers that is responsible for some of the shortest optical pulses available today. In particular, we seek ways to produce from synchronously pumped mode-locked dye laser systems, shorter pulses of higher intensity with improved pulse-to-pulse consistency. Specific topics.that are discussed herein include the study of the role of the pump pulse in synchronously pumped mode-locked lasers, the study of the pulse shaping and shortening due to an intracavity saturable absorber, and the study of a fundamental pulse train instability associated with these lasers.

The Effects Of Bandwidth Limiting Tuning Elements On A Synchronously Pumped Mode-Locked Dye Laser, Bahram Zandi

Dissertations and Theses

In this study an improved description of the bandwidth limiting tuning filters has been introduced into a semiclassical model for a synchronously pumped mode-locked dye laser system. This model is an improvement over the traditional rate equation approach since it has detailed representations of the energy levels, rotational distribution, and coherence effects. The new set of equations has been solved numerically using the best available values for the various parameters, and autocorrelations have been computed for a range of different length detuning and bandwidth limiting elements. In the experiments, an acousto-optically mode-locked argon ion laser is used to synchronously pump …

Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern

Electrical & Computer Engineering Faculty Publications

Silicon-doped n-type gallium arsenide crystals, compensated with diffused copper, were studied with respect to their application as photoconductive, high-power closing switches. The attractive features of GaAs:Cu switches are their high dark resistivity, their efficient activation with Nd:YAG laser radiation, and their microsecond conductivity decay time constant. In the authors' experiment, electric fields are high as 19 kV/cm were switched, and current densities of up to 10 kA/cm² were conducted through a closely compensated crystal. At field strengths greater than approximately 10 kV/cm, a voltage `lock-on' effect was observed.

An Application Of Bit Level Systolic Arrays On Digitized Adaptive Array Processes, Shin-Hwa Tsai

Theses

This thesis has concentrated on some aspects of adaptive arrays, i.e., the data type as well as the calculating processes under an optimized version. An adaption of a modified bit-level array is described on the control structure for processes like correlation matrix, Q-R decomposition and solution of triangular linear systems. In short, an implementation of SMI(Sample Matrix Inversion) under a parallel systolic array process is consider5ed. Also an application of utilizing systolic array on a matrix inversion is derived. As a result, it could be predicted that a VLSI chip implementation for small adaptive arrays is feasible in the near …

Netexpert, An Expert System For Computer Network Management, Sailen Patel

Theses

Data Communications systems consist of distributed software and hardware components executing concurrently a number of communications functions. The logical framework for these functions is called data communication architecture and is layered hierarchically according to the OSI model. The protocol defines the syntax and semantics of the communications between entities of the same layer. NETEXPERT: An Expert system described here contains a set of formal specifications corresponding to different abstractions level of the protocol. On the highest level there is a specification of the service provided by this protocol. On the consecutive lower levels there are successive refinements of this specification …

Microcomputer Control Of An Ac Induction Motor Using A Pwm Computational Intensive Method, Luther William Schnug

Theses

A three-phase microcomputer based AC Inverter has been developed using a computational intensive PWM algorithm that generates the output bridge switching patterns in real time. This approach utilizes the on-board capabilities of an advanced microcontroller, (a 16-bit 8097 from Intel), to eliminate most of the external hardware, and demands on memory size, required in other designs. This algorithm implements in software the Triangular Modulation Method of PWM generation, and utilizes a trapezoidal approximation to the sinusoidal reference waveform. Brassboard tests have shown that this approximation produces 5th and 7th harmonics that degraded performance, at low speeds. An enhanced algorithm, utilizing …

Charge Transfer Inefficiency Of Buried-Channel Charged Coupled Device Registers For Low Temperature Operation Of Ptsi Infrared Image Sensors, Benjamin Benjamin Esposito

Theses

Buried channel charge coupled devices used as readout registers in PtSi Schottky-barrier detector infrared image sensors were investigated to characterize factors that influence charge transfer efficiency at low temperatures ranging from 38 to 80K. These factors included frequency of operation, background signal, gate voltage, signal level, gate length, and temperature. It was found that increased gate voltage and decreased gate length are most effective in reducing charge transfer efficiency. This was attributed to increased fringing fields between the potential wells involved in charge transfer. As temperature was decreased from 50K to 38K progressively larger trapping losses were observed due to …

A Volume Integral Formulation For Electromagnetic Scattering From Homogeneous Dielectric Bodies, Mark Joseph Povinelli

Electrical Engineering and Computer Science – Theses

In recent years, printed circuit antennas have become very useful in conformal and planar phased array antenna systems. Of particular interest is the radiation and scattering performance of stripline and microstrip printed circuit antenna array-elements used in these systems. These ele­ments are generally made up of a complex three-dimensional distribution of dielectrics and con­ductors, which can include microstrip or stripline feed circuitry on a dielectric substrate. Figure 1 shows the geometry of a typical multilayer printed circuit stripline-fed flared slot antenna, used as an array-element in a multioctave planar phased array antenna. This antenna element design also incorporates a stripline …

Free Carrier Density Profiling By Scanning Infrared Absorption, Jack L. Boone, Michael D. Shaw, Gene Cantwell, William C. Harsch

Electrical and Computer Engineering Faculty Research & Creative Works

A prototype instrument for making contactless measurements of free carrier concentration as a function of the surface coordinates has been developed. The instrument requires minimal sample preparation, and the measurements are nondestructive. Measurements are based upon the free carrier absorption of photons at a wavelength of 10.6 μm. The measurement sensitivity is determined by the ability to resolve small variations in the transmitted wave. These variations can be significantly influenced by changes in sample thickness. A scheme has been devised which eliminates thickness variations by rotating the sample through small angles to achieve a transmission maximum at each data point. …

Variable Angle Spectroscopic Magneto-Optics And Ellipsometry: Application To Dyco Multilayers, Thomas E. Tiwald, William A. Mcgahan, Z. S. Shan, Alan M. Massengale, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

The purpose of this paper is twofold. First, we describe the adaptation of a variable angle spectroscopic ellipsometer (VASE) to magneto-optic measurements covering 3000–8000 Å, and 0 to ±8 kOe. Second, we describe application of VASE to determine Kerr rotation and ellipticity for a series of Dy/Co multilayers prepared by sputter deposition. We report spectroscopic ellipsometric and Kerr effect results for samples exhibiting perpendicular magnetic anisotropy, since these are relevant as magneto-optic recording media.

A Lagrangian For A System Of Two Dyons, Rainer Georg Thierauf

Dissertations and Theses

Maxwell's equations for the electromagnetic field are symmetrized by introducing magnetic charges into the formalism of electrodynamics. The symmetrized equations are solved for the fields and potentials of point particles. Those potentials, some of which are found to be singular along a line, are used to formulate the Lagrangian for a system of two dyons (particles with both electric and magnetic charge). The equations of motion are derived from the Lagrangian. It is shown that the dimensionality constants k and k*, which were introduced to define the units of the electromagnetic fields, have to be equal in order to avoid …

Mulch: A Multi-Layer Channel Router Using One, Two, And Three Layer Partitions, Ronald I. Greenberg, Alex T. Ishii, Alberto L. Sangiovanni-Vincentelli

Computer Science: Faculty Publications and Other Works

Chameleon, a channel router for three layers of interconnect, has been implemented to accept specification of an arbitrary number of layers. Chameleon is based on a strategy of decomposing the multilayer problem into two- and three-layer problems in which one of the layers is reserved primarily for vertical wire runs and the other layer(s) for horizontal runs. In some situations, however, it is advantageous to consider also layers that allow the routing of entire nets, using both horizontal and vertical wires. MulCh is a multilayer channel router that extends the algorithms of Chameleon in this direction. MulCh can route channels …

Thin-Film Hermeticity: A Quantitative Analysis Of Diamond-Like Carbon Using Variable Angle Spectroscopic Ellipsometry, S. Orzeszko, Bhola N. De, John A. Woollam, John J. Pouch, Samuel A. Alterovitz, David C. Ingram

Department of Electrical and Computer Engineering: Faculty Publications

The purpose of this paper is twofold. First, we report on the successful application of variable angle spectroscopic ellipsometry to quantitative thin-film hermeticity evaluation. Secondly, it is shown that under a variety of film preparations and moisture introduction conditions water penetrates only a very thin diamondlike carbon (DLC) top surface-roughness region. Thus DLC is an excellent candidate for use as protective coatings in adverse chemical and aqueous environments.

Variable Angle Of Incidence Spectroscopic Ellipsometric Characterization Of Tio2/Ag/Tio2 Optical Coatings, Kazem Memarzadeh, John A. Woollam, Abe Belkind

Department of Electrical and Computer Engineering: Faculty Publications

Optical constants (3000–8000 Å) and layer thicknesses of TiO₂/Ag/TiO₂ optical coatings are determined using variable angle of incidence spectroscopic ellipsometry. Ellipsometrically determined silver layer thicknesses agree well with those obtained by cross-sectional transmission electron microscopy. Also, spectral characteristics, absent in bulk silver data, are observed in n and k spectra for the thin silver layers. It is suggested that these structures may be caused by plasmon effects from the silver layers.

Waveform Analysis And Application To A Model Of The Egg Waveform, Eu-Rune Chang

Theses

The purpose of thesis is to describe and investigate a model of electroglottogram waveform. At the beginning, we generate a set of sine waveform models to analyze by using Fourier transform theory. Then, according to the electroglottogram is conjectured to be related to the area contact between the vocal folds, we assume a simple model of vocal fold vibratory motion is used to estimate the vocal fold contact area as function of time. Therefore, we modified and developed the mathematic EGG waveform model by using personal computer program computation to become a set of realistic EGG waveform models, which are …

Optimal Cache Size In Microprocessor-Based Multiprogramming System, Charalambos Stephanou Christou

Theses

The Motorola 68020 microprocessor, its paged memory management unit MC68851 and cache memories are rigorously studied. The simulation model of this uniprocessor, multiprogramming system was constructed and tested to determine the optimal physical cache size.

The parameters varied in the model are the cache size, the degree of multitasking, the loop count and size, the cache algorithm and the time slice given to every task. A number of simulations have been conducted and the results are examined.

Kalman Filtering Applied To The Analysis Of Brainstem Auditory Evoked Potentials, Chong An Qian

Theses

The objective of this thesis is to detect the Brainstem Auditory Evoked Response (BAER) using lower numbers of averages than at present, by using an optimal smoothing method which is based on the Kalman Filter.

By using this method, the wave V latency of the BAER which is useful in testing for hearing loss can be detected with as low as 500 averages, while the traditional signal averaging method requires at least 2000 averages. Thus the time required for a hearing loss test can be reduced from one hour to approximately 20 minutes.

Also several other methods for detecting BAER …

Learning System, Bhavesh T. Adani

Theses

Many rule-based learning systems have been implemented which generate and update rules/facts from illustrative examples provided by the user. But very few of them have succeeded in achieving the efficiency and accuracy of an ideal system.

The approach made here is to continuously update the hierarchical structure of rules/facts of a knowledge-base so that efficient and accurate solutions to any query can be achieved easily and immediately from the many possible solutions to the query. As the rule-based systems deal with a very large knowledge-base, it is sometimes necessary to apply a learning technique that finds optimum solutions efficiently.

The …

Analysis And Design Of A Surface Microengineered Silicon Humidity Sensor, Uei-Yanq Chen

Theses

This thesis details the design for a solid-state humidity sensor which utilizes state-of-the-art silicon technology. The sensor design utilizes a microengineered surface which includes a polysilicon airbridge structure as heater and sensor element in an integrated device.The operation of this device depends upon the small variation of thermal convection coefficient which effects the temperature of the heated element within the device. The temperature of the polysilicon bridge is monitored by means of a resistance bridge. In one design(sensor I) a single polysilicon airbridge is used for both the heater and resistance sensing element. Also a second inferior design (sensor II) …

Estimation Of X-Band Scattering Properties Of Tree Components, David E. Pitts, Gautam D. Badhwar, Eddie Reyna, R. Zoughi, Linkim Wu, Richard K. Moore

Electrical and Computer Engineering Faculty Research & Creative Works

An X-band FM-CW very fine range resolution scatterometer was used to acquire backscattering data for individual branches for a number of tree species. Using a model to describe the scattering source function, dσ/dR = f(η, κ), and an experimental procedure for selected removal of plant parts, allows the estimation of η, the volume backscatter coefficient, and κ, the volume extinction coefficient. It is found that 1) leaves are strong attenuators as well as scatterers, 2) the albedo, ω = η/κ, at a given angle of incidence, is nearly independent of the tree type, 3) the tree …

Division-Of-Wave-Front Thin-Film Beam Splitter For Generating Binary Patterns Of Orthogonal Elliptical Polarization States, R. M.A. Azzam

Electrical Engineering Faculty Publications

A division-of-wave-front thin-film beam splitter is described that reflects monochromatic light at oblique incidence with orthogonal elliptical polarization states. It consists of a metallic substrate partially covered with a transparent thin film that inverts the ratio ρ of the complex p and s reflection coefficients at the principal angle of the metal. Any pattern of coated and uncoated areas of the substrate is imprinted upon the reflected wave front as a corresponding two-dimensional spatial binary polarization pattern. A specific design is given that uses a Au substrate at a wavelength of 632.8 nm. The effects of small errors in the …

Thin-Film Devices For Polarized Light- Introduction, R. M.A. Azzam, William H. Southwell

Electrical Engineering Faculty Publications

No abstract provided.

Istemcr : Integrated System For Truck Engine Monitoring Via Cellular Radio, Tse-Shan Pan

Theses

The study presented is aimed at the application of the Data Acquisition to The Truck Engine as the source of all the signals, with the mobile telephone Cellular Radio system.

Extrema Of The Magnitude And The Phase Of A Complex Function Of A Real Variable: Application To Attenuated Internal Reflection, R. M.A. Azzam

Electrical Engineering Faculty Publications

Given a complex function F(ω) = |F(ω)|exp[jΔ(ω)] of a real argument ω, the extrema of its magnitude |F(ω)| and its phase Δ(ω), as functions of ω, are determined simultaneously by finding the roots of one common equation, Im[G(ω)] = 0, where G= (F′/F)² and F′ = ∂F/∂ω. The extrema of |F| and Δ are associated with Re G < 0 and Re G > 0, respectively. This easy-to-prove theorem has a wide range of applications in physical optics. We consider attenuated internal reflection (AIR) as …

Physical Mechanism Of Triggering In Trigatron Spark Gaps, F. E. Peterkin, P. F. Williams

P. F. (Paul Frazer) Williams Publications

Since the first trigatron spark gap was described by J. D. Craggs, M. E. Haine, and J. M. Meek [J. Inst. Electr. Eng. 93A, 963 (1946)], there has been controversy about the physical mechanism responsible for triggering the devices. In this letter we present experimental evidence that directly shows the sequence of physical events responsible for triggering in the gap we studied, and we present a model for trigatron triggering based on this information. We believe this model to be general and discuss it in light of existing literature. We briefly discuss the implications of the model for the engineering …

Cmos Sram Design For Initializing Programmable Logic Devices, Ravi K. Vaidyanathan

Theses

This thesis presents the design of CMOS Static Random Access Memory (SRAM) which is imbedded within a high performance Programmable Logic Device (PLD). The SRAM and its control circuitry are used to initialize (or personalize) the NJIT PLD chip. The design is defined in 3-levels of functional hierarchy consistent with the physical and electronic design automation utilized for this design. The imbedded SRAM supports the PLD application circuit which includes 8 small Array and one large Control Programmable Logic Arrays.

The SRAM is structured as 64 X 138 bit array with serial read and write inputs. It is designed emphasizing …

Research, Development, And Evaluation Of A Solid State Transformer, Robert Michael Joseph Wozniak

Theses

The analysis and design of a solid state step down transformer is presented as part of a research study which reviews novel approaches to the development of high frequency power magnetic apparatuses and applies available theory to produce a solid state counter part. The resulting circuit exhibits the potential for efficiency as high as 85%, low output ripple, regulation that is comparable with other modes of power conversion and the ability to provide localized on-board power.

C/Ku Band Satellite Television Reception System, Costas A. Economides

Theses

The purpose of this thesis is to examine and investigate the design of a satellite reception system able to receive most C and Ku band North American geostationary satellites' TV transmissions. The performance criterion used for the system design is based on a required demodulated video signal-to-noise ratio maintained for a specified percentage of time in conjunction with overall cost considerations.

Furthermore, a computer program written in FORTRAN 77 is developed, which among other functions lists the notified, operational, geostationary satellites in sight with their corresponding look angles, from any given location on the earth.

A Silicon Photodiode Array For Soft X-Ray Sensing, Chih-Te Hu

Theses

An array of 30 x 30 sensing cells including logic within each cell and a self-scan address circuit are described. A unique scintillation technique is used to increase the threshold sensitivity 60dB for X-ray photon sensing beyond that obtainable with conventional photodiode sensors. Simulations for the sensing cell and some additional logic elements are based on SPICE version 2G5 and HILO 3. Worst case analysis includes variations in threshold voltage V_TP and V_TN for the CMOS circuit components. The final CMOS chip dimension using MOSIS 1.2 micron rules is 10mm x 10mm base on the 80 …

Modeling And Simulation Of Robot Arms With Flexible Links, John G. Danis

Theses

The design of lightweight robot arms introduces a degree of flexiblity in the individual links which renders the arm difficult to control. Solution of the control problem requires accurate and detailed mathematical models of the arm dynamics. A comprehensive survey of the current literature in this area has shown that although many such models exist, there is a great diversity in their structure, function, and applicability. The different objectives and techniques of model development which lead to this diversity are examined and summarized in this thesis. Bases for classification of the mathematical models and techniques of development are established, and …