Physics Commons^™

Design Of A Resonant Optical Cavity For Imaging Magneto-Optically Active Thin Film Samples, Cody Robert Brelage

Graduate Theses - Physics and Optical Engineering

This document describes the design and fabrication of an optical resonator system to investigate magneto-optic properties of thin film samples. This system uses an open-air optical resonator to enable photons to make multiple passes through each thin film and thus increase the magnitude of the Faraday rotation that each sample imposes onto the light that exits the system. This system promises many future experiments to study the magneto-optic properties of thin film and nano-particle samples. Using an optical resonator to enhance Faraday rotation should enable an improved signal-to-noise ratio in taking measurements and images with a photodetector.

Metasurfaces For Nano-Illumination In Lidar And Lighting Applications, Sehyeon Kim

Graduate Theses - Physics and Optical Engineering

The development of a non-scanning laser-based imaging lidar system based on a diffractive optical element with potential applications in advanced driver assistance systems, autonomous vehicles, drone navigation, and mobile devices is reported. The proposed lidar utilizes image processing with homography. The emphasis in the design approach has been on compactness and cost of the final system for it to be deployable both as standalone or complementary to existing lidar sensors, enabling fusion sensing in the applications. This work describes the basic elements of the proposed lidar system. It presents the potential ranging mechanisms, along with their experimental results demonstrating the …

Distributed Feedback Master Oscillator Power Amplifier Using Interface Polaritons, Dongwon Jang

Graduate Theses - Physics and Optical Engineering

Characterization and simulation of an innovative solid-state distributed feedback master oscillator power amplifier (solid-state DFB MOPA) are presented, using interface polaritons (IPs) that enhance wave propagations at gain-loss interfaces in active layers. The author set up the design of the fabricated device, and a company, Freedom photonics, collaborated with us, allowing me to modify some of their designed MOPA systems. The master oscillator (MO) consists of a patterned grating on a waveguiding region to transfer only a single mode of 1.550 μm wavelength. The power amplifier (PA) is fabricated with the MO to reduce power loss and tapered to amplify …

Design And Fabrication Of Biaxial Hyperbolic Metamaterials, Changkee Hong

Graduate Theses - Physics and Optical Engineering

This thesis describes a new method for fabrication of biaxial hyperbolic metamaterials (BHMMs) using layered structures consisting of oblique angle deposited (OAD) titanium dioxide (TiO2) and copper (Cu). An oblique angle deposition (OAD) technique was utilized to deposit dielectric layer composed of nanocolumnar structures in order to provide biaxial property. The biaxial hyperbolic dispersion of the fabricated BHMM was characterized via profilometer and variable angle spectroscopic ellipsometry (VASE) measurements for wavelength between 381 nm and 894 nm. For the fabricated BHMM, a noticeable difference of 0.13 - 0.001 between the in-plane permittivity components and dual epsilon-near-zero (ENZ) regions which are …

Modeling And Characterization Of A Ring-Resonator Based Silicon Photonic Sensor On Silicon-On-Insulator (Soi), Gwangho Choi

Graduate Theses - Physics and Optical Engineering

The purpose of this work is to build silicon photonic devices and verify their functionalities. In particular, the structure of a ring resonator (RR) is analyzed and applied to various silicon photonic application in sensing. Silicon waveguides, grating couplers, directional couplers, and RRs are fabricated on the silicon-on-insulator (SOI) wafer. Geometrical parameters and optical properties of the silicon devices are studied and also applied to the design of the aforementioned devices. The waveguide dimensions and, optical properties of the silicon waveguide such as dispersion and effective-index are examined. The RRs are made of a series of straight and bent waveguides …

Design, Fabrication, And Characterization Of Multilayer Hyperbolic Metamaterials, James Dilts

Graduate Theses - Physics and Optical Engineering

Hyperbolic metamaterials (HMMs) show extreme anisotropy, acting as metals and dielectrics along orthogonal directions. They are designed using the effective medium theory (EMT) and can be fabricated using standard semiconductor processing techniques. Current techniques used to characterize the optical behavior of HMMs have a high complexity or are unable to robustly determine the complex permittivity tensor. We describe the details of a procedure to obtain a very low mean-squared-error (MSE) for extraction of permittivity from hyperbolic metamaterials using spectroscopic ellipsometry. We have verified our procedure by fabricating three different samples of various materials and fill factors designed to have a …

Hybrid Optical Integrator Based On Silicon-On-Insulator Platform, Taewon Huh

Graduate Theses - Physics and Optical Engineering

A hybrid optical integrator is a recirculating loop that performs oversampling typically for analog input, using the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). The modulated input signal changes the gain of the loop through XGM and thus modifies the loop accumulation. This thesis presents hybrid optical integrator for an all-optical analog-to-digital converter based on a silicon photonics platform. The device consists of silicon waveguides of dimension 220 × 500 nm (thick × width) and approximately 5 m optical loop length including fiber length, input and output grating couplers for 1550 nm signal, directional couplers, and external components …

Tilt Measurements Using A Monolithic Cyclic Interferometer, Joseph Porter

Graduate Theses - Physics and Optical Engineering

Measurement applications globally are demanding higher resolution measurements within a smaller footprint. The cyclic interferometer is a proven means of high-resolution tilt measurements while maintaining fringe stability. However, the cyclic interferometer commonly has many optical elements over a large surface area. In this thesis, a monolithic cyclic interferometer has been designed, constructed, and characterized. The monolithic system contains all the functionality of a typical cyclic interferometer, yet the optical elements are contained within a single glass optic. In doing so, the system attains a compact form factor and it is possible to complete measurements within a broader field of application.

Coupling Light Into Siliconwaveguide Using Surface Plasmon Polaritons, Jeong Rok Kim

Graduate Theses - Physics and Optical Engineering

No abstract provided.

Design, Fabrication, And Characterization Of A One-Dimensional Single-Material Polarizing Photonic Crystal, Ehsan Ordouie

Graduate Theses - Physics and Optical Engineering

We examine a multilayered one-dimensional (1D) polarizing photonic crystal designed and fabricated out of a single material. This polarizer is designed for high reflection of the s polarization and low reflection of p polarization at the wavelength of 632.8 nm. This device is fabricated implementing the oblique angle deposition technique to produce six-bilayers of alternating high to low indices of titanium dioxide using e-beam PVD for depositing on top of a fused silica substrate. For modeling, we used transfer-matrix method and numerical finite-difference time-domain analysis to simulate behavior of the 1D photonic bandgap structure. Both model and simulation predict better …

Gain Modeling Of Erbium-Doped Fiber Amplifiers Pumped At 980nm, Deepak Charles Baskar

Graduate Theses - Physics and Optical Engineering

Erbium-Doped Fiber Amplifiers (EDFA) are one of the most widely used optical amplifiers in the field of optical communications and fiber lasers. Theoretical models based on the rate equations, therefore, were developed to predict the performance of such amplifiers. The goal of this thesis is to provide a numerical model for EDFAs and verify its validity through experimental measurements. Two computer programs based on two different numerical methods (the Finite Difference method and the 4th Order Runge-Kutta Method) to solve differential equations were written. The different fiber parameters to build the model including absorption and emission crosssections and scattering losses …

The Simulation, Design, And Fabrication Of Optical Filters, John-Michael Juneau

Graduate Theses - Physics and Optical Engineering

The purpose of this thesis is to create a model for designing optical filters and a method for fabricating the designed filters onto a multitude of substrates, as well as to find ways to optimize this process. The substrates that were tested were quartz, glass slides, polycarbonate, and polyethylene terephthalate (PET). This work will account for variations in the deposition process and substrate cleaning method, in order to optimize the performance of the final optical filter. Several different filters were simulated and then fabricated. These filters included 3, 5, and 7-layer Bragg reflectors, 11-layer narrowband filters, and some variations of …

Fabrication And Characterization Of Thermo-Optic Mach-Zehnder Silicon Modulator, Yeongho Park

Graduate Theses - Physics and Optical Engineering

This thesis focuses on the modeling, design, and fabrication of the Thermo-Optic Mach-Zehnder Modulator, which is one of the simple active devices in silicon photonics. The Mach-Zehnder interferometer (MZI) was formed as an optical path on a silicon on insulator (SOI) wafer of 2040±80 nm thick, and the thermo-optic effect was used to modulate the infrared light of 1553 nm wavelength by controlling the temperature of the one arm of the MZI. To fabricate and understand the Si photonic device, the whole process from theory to the measurement setup is introduced. Additionally, all the fabrication details and some informative experiments …

Construction And Passive Q-Switching Of A Ring-Cavity Erbium-Doped Fiber Laser Using Carbon Nanotubes As A Saturable Absorber, Austin Scott

Graduate Theses - Physics and Optical Engineering

The purpose of this thesis is to design, build, test, and achieve pulsed operation of a ring-cavity erbium-doped fiber laser using carbon nanotubes as a saturable absorber. The erbium-doped fiber is characterized first, cross-sections are calculated, and the gain value is determined. Subsequently, the ring cavity is constructed and the laser is operated in the continuous wave regime. Much time is then spent trying to characterize and utilize the carbon nanotubes successfully. Many dispersions are made using multiple solvents and dispersing media, various images are taken with both scanning electron and Raman microscopy, and attempts at purification are made. Saturable …

Nanoscale Tilt Measurement Using A Cyclic Interferometer With Phase Stepping And Multiple Reflections, Tahereh Naderishahab

Graduate Theses - Physics and Optical Engineering

High accuracy tilt or roll angle measurement is required for a variety of engineering and scientific applications. Optical interferometry is normally used because it is non-contact and can measure tilt with a very high degree of accuracy. In this thesis, a cyclic interferometer has been developed with four mirrors to measure tilt angles as small as a few nanoradians. To measure the phase, a novel and simple method of phase shift by polarization was developed to enhance measurement sensitivity and accuracy. Since the cyclic interferometer is insensitive to external vibrations and turbulences, polarization phase step was accomplished with relative ease. …

Design And Implementation Of A Microscope Based On Magneto-Optic Effects, Yuxuan Liu

Graduate Theses - Physics and Optical Engineering

When light passes through a medium that is subjected to a strong magnetic field, its polarization state may change due to magneto-optic effects such as Faraday rotation. An imaging system based on this polarization change is designed and constructed. The imaging system is built around a magnetic pulse field generator and able to detect polarization change of the incident light due to magneto-optic effects. An automated scheme is implemented using LabView. The program is developed to integrate all hardware and conduct multiple measurements automatically to enhance sensitivity. Basic testing measurements are conducted to evaluate the performance of the system. A …

Designs And Reliability Evaluations Of A Scattered Light Measurement System, Kang-Min Lee

Graduate Theses - Physics and Optical Engineering

The purpose of my work was to develop an in-plane stray light measurement system having the advantage of being easily applicable in both motion control and optical configurations. First of all, mechanical designs were conducted based on both 3D modeling and structural analysis through a finite element method (FEM). Optical configurations for both the incident source and the detector were designed to achieve minimum observed source convergence angle of the system. The control panel and micro stepping system were programmed for automated measurement. Finally, the designed system was calibrated and aligned. In order to evaluate the system reliability for scatter …

Surface Roughness Effects On Light Propagation In Optical Light Pipes, Youngjin Park

Graduate Theses - Physics and Optical Engineering

Solid- and hollow-core light pipes are commonly employed to shape the intensity profile of high power lasers for applications in various technology industries such as the automobile, medical, and communications. There are several loss mechanisms present in solid-core glass and polymer light pipes, including absorption, bulk scattering in the material, surface scattering at the material-air interface, and Fresnel Loss at the material-air interface. Fresnel reflection and surface scattering losses typically dominate over other loss mechanisms in solid-core light pipes made of high quality optical materials. In order to analyze the losses in the light pipe, an approximate model is developed …

Optical Bistability In A Vcsel Coupled To Serially-Connected Pin Photodiodes Quantizer Device, Sanaz Faryadras

Graduate Theses - Physics and Optical Engineering

In this work we investigated the structure and performance of vertical cavity surface emitting lasers (VCSEL) which will be used in building an optical quantizer. In any p-i-n structure, capacitance is the most important factor in deciding the highest modulation speed. Therefore, components with smaller capacitance would show higher switching speed. A novel electrical quantizer was constructed using two identical 850 nm Finisar VCSELs, which could manifest electrical switching up to 1.4 MHz. Also, a new electrical quantizer was built with two Eudyna PIN photodiodes (PD-PD), which works at higher frequencies up to 8 MHz, comparing to previous works. The …

Development And Validation Of An Empirical Temperature-Dependent Voltage Model For Diode Laser Characterization, Grant Matthew Brodnik

Graduate Theses - Physics and Optical Engineering

This work investigates the effects of temperature on the operation and performance of indium-phosphide (InP) based high-power broad-area laser (BAL) diodes operating in the eye-safe regime (1.5 μm – 2.0 μm). Low temperature (-80C to 0C) operation using a cryogenically cooled system enables investigation of temperature-dependent parameters such as threshold current, slope efficiency, diode voltage, and power conversion efficiency (PCE) of devices. Building upon established empirical models that describe threshold current and slope efficiency as functions of temperature, a key additional parametric model is developed to describe diode voltage incorporating a temperature dependence. With the inclusion of this temperature-dependent voltage …

Bending Loss Mitigation By Surface Plasmon Resonance, Daniel Steven Spoor

Graduate Theses - Physics and Optical Engineering

Surface plasmon resonance can be used to confine a wave within a thin metal film. The resultant wave is very well-confined by the extreme refractive index difference between the metal and the ambient medium. Such confinement can be used to guide waves under extreme conditions such as subwavelength channels or through extremely tight bends where radiation losses would normally dissipate the wave.

A nichrome thin film was deposited and etched as a shadow alongside a series of multi-mode SU-8 slab waveguides with extremely sharp angled bends. Light from a Helium-Neon laser was coupled into these waveguides and the power transmitted …

Study Of Surface Plasmon Resonance In Metal And Alloy Nanofilms Using Maxwell Description And Metamaterial Simulation In Comsol, Heesoo Park

Graduate Theses - Physics and Optical Engineering

Metamaterials are artificial metallic structures having, possibly, simultaneously negative permittivity and negative permeability which is called a double negative medium. To achieve a visible light range of the metamaterial, the unit cell of the metamaterial units should be 10-200nm. It is a much bigger structure than a size of normal atom. Still, the resolution of fabrication, which is difficult part, should typically be a few nanometers to achieve a nano-level unit. We study Ag thin-film as a convenient candidate for metamaterial over a specific frequency range. Because, the thin film metal is composed of disk shape island structures itself. These …

Increasing The Sensitivity Of The Michelson Interferometer Through Multiple Reflection, Woonghee Youn

Graduate Theses - Physics and Optical Engineering

Michelson interferometry has been one of the most famous and popular optical interference system for analyzing optical components and measuring optical metrology properties. Typical Michelson interferometer can measure object displacement with wavefront shapes to one half of the laser wavelength. As testing components and devices size reduce to micro and nano dimension, Michelson interferometer sensitivity is not suitable. The purpose of this study is to design and develop the Michelson interferometer using the concept of multiple reflections. This thesis proposes a new and novel design for a multiple reflection interferometer, where the number of reflections does not affect the quality …

Study Of Laser Speckle Scattering In Vitreous Humor Models, Wanseok Oh

Graduate Theses - Physics and Optical Engineering

When a highly high coherent light propagates through a medium, interactions between light and the medium produces a unique intensity speckle pattern that is dependent on several factors such as particle size in the medium, wavelength of the light, concentration of medium, and scattering angle. Speckle patterns from either static or dynamic specimens have been studied using optical techniques due to its non-invasive nature. Speckle patterns from biological specimens (dynamic) are different from that of the static specimens since random movement of molecules (Brownian motion) in the biological specimen affect the light interactions and thereby the intensity of the speckles …

Optical Bistability With Two Serially Integrated Inp-Soas On A Chip, Michael Edward Plascak

Graduate Theses - Physics and Optical Engineering

A photonic switch using two series-connected, reverse-biased semiconductor optical amplifiers integrated onto a single device has been proposed and switching operation has been verified experimentally. The switching operates on two principles; an electrical bistability arising from the connection of two p-i-n structures in series, and the quantum confined Stark effect in reverse-biased multiple quantum well structures. The result is an electroabsorption modulation of the light through the SOAs due to the alternating voltage states. The system simultaneously produces outputs with both inverted and non-inverted hysteresis behavior, with experimental switching speeds demonstrated up to 400 kHz for a reverse-bias voltage of …

Quantitative Data Extraction Using Spatial Fourier Transform In Inversion Shear Interferometer, Yanzeng Li

Graduate Theses - Physics and Optical Engineering

Currently there are many interferometers used for testing wavefront, measuring the quality of optical elements, and detecting refractive index changes in a certain medium. Each interferometer has been constructed for a specific objective. Inversion shear interferometer is one of them. Compared to other interferometers, it has its own advantages, such as only being sensitive to coma aberration, but it has some limitations as well. It does not allow use of phase shifting technique. A novel inversion shear interferometer was invented using holographic lenses. By using the spatial carrier method, phase information of the wavefront was extracted. The breakthrough of the …

A Study Of Scattering Characteristics For Micro-Scale Rough Surface, Yonghee Won

Graduate Theses - Physics and Optical Engineering

Defining the scatter characteristics of surfaces plays an important role in various technology industries such as the semiconductor, automobile, and military industries. Scattering can be used to inspect products for problems created during the manufacturing process and to generate the specifications for engineers. In particular, scattering measurement systems and models have been developed to define the surface properties of a wide variety of materials used in manufacturing. However, most previous research has been focused on very smooth surfaces as a nano-scale roughness. The research in this paper uses the Bidirectional Reflectance Distribution Function (BRDF) and focuses on defining the scattering …

All-Optical Sigma-Delta Modulator For Analog-To-Digital Conversion, Bin Zhang

Graduate Theses - Physics and Optical Engineering

In this thesis, an all-optical sigma-delta (ΣΔ) modulator for analog-to-digital conversion (ADC) using a novel optical bistable switch, the SOA-PD device, is demonstrated. The presented all-optical ΣΔ modulator consists of a photonic leaky integrator, the SOA-PD optical comparator, and a positive feedback loop. The switching properties of the SOA-PD device are studied and experimentally tested to confirm its performance. Then the all-optical ΣΔ modulator is designed according to the switching performance of the SOA-PD device. It is demonstrated that the all-optical ΣΔ modulator is capable of producing an inverted non-return-to-zero (NRZ) type binary output for frequencies in the range of …