Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--York University, 2005. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 218-233). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11637

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The infrar-red spectra of gaseous HC=CCHO, DC=CCHO, HC=CCDO and the Raman spectrum of liquid HC=CCHO has been measured and analysed to give the normal vibrational frequencies of the molecule in the electronic ground state. The electronic band spectrum of propynal with origin at 4144 A has been photographed under low resolution in both emission and absorption and analysed in terms of the vibrational frequencies associated with the combining electronic states. The origin band for both HC=CCHO and DC=CCHO has been photographed under high resolution and a partial rotational analysis is presented for this band. The transition responsible for the electronic spectrum has been identified as being of n ->3pi*, 3A"<- 1A' type, and the observed spectrum confirms the theoretical predictions as to the structure that results from a transition of this type. / Thesis / Doctor of Philosophy (PhD)

Large-scale optoelectronic integration is limited by the lack of efficient light sources and broadband photodetectors, which could be integrated with the silicon complementary metal-oxide-semiconductor (CMOS) technology. Persistent efforts continue to achieve efficient light emission as well as broadband photodetection from silicon in extending the silicon technology into fully integrated optoelectronic circuits. Recent breakthroughs, including the demonstration of high-speed optical modulators, photodetectors, and waveguides in silicon, have brought the concept of transition from electrical to optical interconnects closer to realization. The on-chip light sources based on silicon are still a key challenge due to the indirect bandgap of silicon that impedes coherent light sources. To overcome this issue, we have studied, fabricated, and characterized nanostructures including single semiconductor epilayers, multiple quantum wells, and graphene-semiconductor heterostructures to develop coherent light sources and photodetectors in silicon. To develop coherent light sources, we reported the demonstration of room-temperature lasing at the technologically crucial 1.5 m wavelength range from Er-doped GaN epilayers and Er-doped GaN multiple-quantum wells grown on silicon and sapphire. The realization of room-temperature lasing at the minimum loss window of optical fiber and in the eye-safe wavelength region of 1.5 m is highly sought-after for use in many applications in various fields including defense, industrial processing, communication, medicine, spectroscopy and imaging. The results laid the foundation for achieving hybrid GaN-Si lasers providing a new pathway towards full photonic integration for silicon optoelectronics. Silicon photodiodes contribute a large portion in the photodetector market. However, silicon photodetectors are sensitive in the UV to near infrared region. Photodetection in the mid-infrared is based on thermal radiation detectors, narrow bandgap materials (InGaAs, HgCdTe) semiconductors, photo-ionization of shallow impurities in semiconductors (Si:As, Ge:Ga), and quantum well structures. Such technology requires complicated fabrication processes or cryogenic operation, resulting in manufacturing costs and severe integration issues. To develop broadband photodetectors, we focus on graphene photodetectors on silicon. Graphene generates photocarriers by absorbing photons in a broadband spectrum from the deep-ultraviolet to the terahertz region. Graphene can be realized as the next generation broadband photodetection material, especially in the infrared to terahertz region. Here, we have demonstrated high-performance hybrid photodetectors operating from the deep-ultraviolet to the mid-infrared region with high sensitivity and ultrafast response by coupling graphene with a p-type semiconductor photosensitizer, nitrogen-doped Ta2O5 thin film. / Doctor of Philosophy / According to Moor's law, the number of transistors per die area doubles every 18 months with no increase in power consumption, which means that digital devices including smart phones and computers will become significantly faster and more energy-efficient than those of the previous generation. Photons (light) travel with the highest speed permitted by the known law of physics. The idea of optical interconnects, using photons instead of electrons, enables faster data transfer. Two important elements of the integrated circuits (ICs) based on photons are the coherent light source (laser) and the photodetector. We investigated the optical properties of erbium doped gallium nitride epilayers and multiple quantum wells grown on silicon and sapphire and demonstrated lasing from these materials at 1.5 µm. We also fabricated and characterized graphene photodetectors that can detect the light from the deep ultraviolet to the mid-infrared region. The results provided a new pathway towards full photonic integration for silicon optoelectronics. Besides, they are the heart of many important applications ranging from gas sensing, aerospace sensors and systems, thermal imaging, biomedical imaging, infrared spectroscopy, and lidar-to-optical telecommunications.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Efforts are underway to develop Infrared countermeasure (IRCM) systems to defend aircraft against IR guided surface-to-air (SAM) and air-to-air (AAM) missiles. One such system is the Large Aircraft Infrared Counter Measure (LAIRCM) which employs temporal, spatial, and spectral missile warning techniques. There is no current technique however, for installed system flight testing of such countermeasures in a realistic temporal, spatial, and spectral environment. This paper is an introduction to the Towed Airborne Plume Simulator (TAPS), a system designed to address this test shortfall. The TAPS operational concept is described as well as techniques for simulating missile signatures.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper describes a short distance telemetry network which measures and relays time, space, and position information among a group of ground vehicles. The goal is to allow a lead vehicle to be under human control, or perhaps controlled using advanced autonomous path planning and navigation tools. The telemetry network will then allow a series of inexpensive, unmanned vehicles to follow the lead vehicle at a safe distance. Ultrasonic and infrared signals will be relayed between the vehicles, to allow the following vehicles to locate their position, and track the lead vehicle.

published_or_final_version / Chemistry / Master / Master of Science

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