Electromagnetics and Photonics Commons^™

Design And Fabrication Of An Optical Blade Tip Timing Sensor, Nick Tomlinson

All Theses

Electricity is a vital energy source that powers modern technology. Turbines are heavily relied on in the electric power industry for the conversion of natural energy sources into electricity. These turbines operate under harsh conditions which increase the likelihood of blade damage. Structural health monitoring of a turbine’s blades is important to detect problems before a blade experiences failure. The blade tip timing method can be used to monitor blade vibrations and determine if damage has occurred. An optical blade tip timing sensor is designed and fabricated to advance the field of sensing in the power industry.

Tunable Linewidth Chip-Level Lasers Using Hybrid Integration Methods, Charles Porter

All Theses

Photonic integrated circuits (PICs) have significant value in today’s world of research. They enable devices to experience large reductions in size, weight, operation power, and cost (SWAPc), making photonic technology more accessible than ever. The functionality of PICs is greatly enhanced due to the realization of both active and passive devices within a single device structure. This is made possible through hybrid integration, which utilizes various coupling methods to transfer light from an active chip to a passive chip. Hybrid integration technology tremendously expands the capabilities of PICs, leading to a plethora of applications. One significant application is that of …

A Study Of A Monolithic Pulsed Fiber Laser With High-Peak And Average Power, Mark Mihalik

All Theses

Fiber lasers with high peak power, pulse energy and average power have numerous industrial applications. This project aimed to build a Master Oscillator Power Amplification fiber laser using commercial components and specialty fiber designed by Clemson University to exceed the power and energy targets of a previous Q-switched fiber laser design. The specialty fiber has a low numerical aperture of 0.028 and a unique geometric core design to minimize amplified spontaneous emission and reduce nonlinear effects in order to produce a high-peak power and high per pulse energy. The two stage, monolithic design targets 3.1 mJ per pulse, average power …

Oam-Based Wavelets In A High Speed Optical Probing System For Measuring The Angular Decomposition Of The Environment, Justin Free

All Theses

This thesis presents the theoretical development of orbital angular momentum (OAM) based wavelets for the analysis of localized OAM information in space. An optical probing system for generating and detecting these wavelets is demonstrated; individual wavelets can scan the environment in 10µs or less. The probing system was applied to a three-dimensional atmospheric turbulence distribution to obtain a continuous wavelet transform of the angular information of the turbulent propagation path about a fixed radius. An entire continuous wavelet transform was measured in 3.8ms; the measurements are much faster than the turbulence and give insight into the short time scale of …

Optical Control System For Atmospheric Turbulence Mitigation, Martyn Lemon

All Theses

Propagation of laser light is distorted in the presence of atmospheric turbulence. This poses an issue for sensing, free-space optical communications, and transmission of power. With an ever-increasing demand for high-speed data communications, particularly between satellites, unmanned vehicles, and other systems that benefit from a point-to-point link, this issue is critical for the field. A variety of methods have been proposed to circumvent this issue. Some major categories include the manipulation of the light’s structure, an adaptive scheme at the optical receiver, scanning mirror systems, or a transmission of simultaneous signals with a goal to improve robustness.

There is an …

Design Of Arbitrary Planar Optical Devices With Full Phase Control Using Nanoimprinting Of Refractive Index, Matthew Panipinto

All Theses

Planar optical devices offer a lightweight solution to the constraints found in traditional optical devices. While subwavelength patterning of optics offers attractive performance and size, traditional fabrication methods demand a trade-off between resolution and throughput that presents a significant hurdle for the widespread use of subwavelength devices. Nanoimprinting of refractive index (NIRI) is a novel fabrication method pioneered in previous work that offers promise in mitigating the throughput issues that hamstring traditional fabrication methods. However, NIRI has not been shown to impart full $2\pi$ phase control in planar optical devices, nor has a method for fabricating arbitrary designs using the …

Digital And Gradient Refractive Index Planar Optics By Nanoimprinting Porous Silicon, Anna Hardison

All Theses

Due to the drawbacks of traditional refractive optics, the implementation of planar or nearly planar optical devices has been of research interest for over a century. Subwavelength gratings are a particularly promising option for creating flat optical devices; however, the implementation of subwavelength grating-based optics is limited by fabrication constraints. Recently, we implemented flat optical devices using the nanoimprinting of refractive index (NIRI) process, a process which was pioneered in a previous study but remained largely unproven in terms of device fabrication. The planar, gradient index microlenses we fabricated were found to possess an effective medium similar to a subwavelength …

On The Use Of Natural-Mode Basis Functions For Electromagnetic Analysis Of Arbitrary Conducting Surfaces, Joshua Lawrence

All Theses

The natural modes defined in the singularity expansion method (SEM) are used as basis functions for the frequency- and time-domain current responses of arbitrary perfect electrically conducting (PEC) surfaces in this work. First, a method of determining the natural frequencies and corresponding modes which employs the electric field integral equation is presented. These quantities are then calculated for several geometries and the currents induced due to an incident plane wave in the frequency and time domains are approximated by a weighted sum of the natural modes. Additionally, the modal weights prescribed by SEM are compared to a set of weights …