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This thesis is about the design, fabrication, and characterization of nanophotonic elements in the visible that can enhance light-matter interaction for single quantum emitters. We focus on two material systems: single photon sources based on the nitrogen-vacancy (NV) center in diamond with improved spontaneous emission rates and collection efficiencies, and passive TiO2 devices that comprise a potentially broadband (from the visible to the infrared), low loss photonics platform and that are suitable for probing and manipulating single colloidal quantum dots. We first discuss the requirements for using color center emission in bulk diamond crystals for potential applications in quantum information processing, and provide examples of using nanowire structures and planar resonators made in diamond for engineering the the NV center’s pump and collection efficiencies, and spontaneous emission rates, respectively. We also describe the integration of diamond with plasmonic structures. We have designed and implemented diamond-silver apertures for broadband enhancements of the spontaneous emission rates of NV centers. We show that shallow-implanted NV centers in diamond nanoposts provide a good system for controlling the NV center spontaneous emission rates, allowing for quenched emission with long lifetimes in the bare case, and enhanced emission with fast decay rates (corresponding to a Purcell factor of around 6) when coated with silver. We add plasmonic gratings around the diamond-silver apertures to improve the collection efficiency of the system, and observe over two-fold improvement in collection. We demonstrate the fabrication of chip-scale linear optical elements such as waveguides and racetrack resonators in low-loss \(TiO_2\) thin films. The fabricated waveguides operate over a wide bandwidth with propagation losses from from 30 dB/cm in the visible to 4 dB/cm in the IR, while racetrack resonators can critically couple to waveg- uides and have quality factors as high as ~22000 in the red wavelengths. We present the fabrication of dielectric slot waveguides and their integration with colloidal quan- tum dots. Finally, we describe efforts to study and control charge transfer processes between quantum dots and \(TiO_2\) on a single emitter level. / Engineering and Applied Sciences

High brightness light emitting diodes based on the InAs/GaSb superlattice material system have been developed for use in mid-wave and long-wave infrared optoelectronic systems. By employing a multiple active region device configuration, high optical output has been demonstrated from devices in the 3-5μm and 7-12μm spectral bands. Mid-wave infrared optical output in excess of 0.95mW/sr has been observed from 120×120μm2 devices with peak emission at 3.8μm, and nearly 160μW/sr has been measured from devices of the same size operating at 8μm. Larger devices (1×1mm^2) with output as high as 8.5mW/sr and 1.6mW/sr have been demonstrated with mid-wave and long-wave devices, respectively, under quasi-DC bias conditions. The high switching speed inherent to small area light emitting diodes as well as potentially high optical output make these devices appealing candidates to improve upon the current state-of-the-art in infrared projection technology. Simulation of thermal scenes with wide dynamic range and high frame rates is desirable for calibration of infrared detection systems. Suitable projectors eliminate the need for observation of a live scene for detector calibration, thereby reducing costs and increasing safety. Current technology supports apparent temperature generation of up to approximately 800 Kelvin with frame rates of hundreds of frames per second; strong desire exists to break these barriers. Meeting the requirements of the aforementioned application requires development of the InAs/GaSb superlattice material system on multiple levels. Suppressing parasitic recombination channels via band structure engineering, improving carrier transport between active regions and confinement within active regions, reduction of defect-assisted recombination by optimizing device growth, and improving device fabrication and packaging are all routes requiring exploration. This work focuses on the latter two components of the optimization process, with emphasis on molecular beam epitaxial growth of high quality devices. Particular attention was paid to tailoring devices for thermal imaging applications and the design tradeoffs and limitations which impact that technology. Device performance and optimization success were gauged by electronic, optical, morphological, and structural characterization.

The beginning of X-ray astronomy is based on two accidental discoveries made in 1962. A single point source, Scorpio X-1 and remarkable discovery of the diffuse background radiation, three years before the microwave background was discovered. Over the past four decades, X-ray astronomy has matured into a major branch of astronomy, contributing to our understanding of the physical processes operating in many different types of sources, from stars to high redshift quasars. In 1990, the launch of the ROSAT satellite offered to unique opportunity to investigate the radio properties of X-ray emitters. A sample of faint X-ray emitters from a deep pointed observation is used in this thesis to investigate the prediction that sub-mJy radio source are a major contributor to the X-ray background. Another sample of 695 bright X-ray emitters were selected from ROSAT All Sky Survey for optical follow-up as a European Southern Observatory key project. The radio follow-up of the sample was undertaken for this thesis. The aim is to construct a catalogue of radio emitting X-ray (REX) sources to study their quantitative statistical properties and to select out a sample of BL-Lac objects for further study. Based on previous surveys approximately 19% or 130 of the X-ray sources should be directly associated with a radio emitter, of which 90% will be positionally coincident with the most plausible optical candidate for an X-ray source. This increases the efficiency of the optical identification program by about 15 percent. / Doctor of Philosophy (PhD)

No description available.

Targeted radiotherapy (TRT) is a technique which allows for individual cancer cells to be targeted by radiation. However, there is variation in uptake at the whole body, organ, cellular and subcellular levels. This distribution affects the biological efficacy of the TRT agents. To address this problem, novel techniques have been developed and demonstrated. These aim to provide quantitative information about the spatial distribution of Auger electron (AE) emitting radiopharmaceuticals at the subcellular level. Two methods have been developed. The first, photoresist autoradiography (PAR), uses photoresists as an autoradiography substrate, and the second uses microautoradiography (MAR) and a transmission electron microscope (TEM). The techniques have been demonstrated using the AE emitter indium-111. Firstly, PAR is demonstrated using poly (methyl methacrylate) (PMMA). Photoresists were exposed to indium-111 which had been internalised into cells, and the photoresists were analysed using atomic force microscopy (AFM). The technique has a theoretical resolution in the nanometre range and was able to demonstrate cellular patterns on the micron scale. To gain quantitative information, the photoresist response (depth of pattern) was calibrated as a function of electron fluence and a model of the patterns was created. Combining the calibration data with the point source model allowed the position and intensity of the internalised source terms to be estimated using the PAR method. Secondly, a technique for electron microscope-microautoradiography (EM-MAR) was developed. The processing conditions of the MAR technique were determined and staining techniques developed, to produce high quality TEM micrographs. A time course experiment showed the distribution and variation in the uptake of the radiopharmaceutical at the cellular level. Both techniques are able to provide information about the subcellular distribution of the radioactivity at a higher resolution than current techniques. Both enable the collection of information which can be used in microdosimetric calculations.

No description available.

abstract: Research and development of organic materials and devices for electronic applications has become an increasingly active area. Display and solid-state lighting are the most mature applications and, and products have been commercially available for several years as of this writing. Significant efforts also focus on materials for organic photovoltaic applications. Some of the newest work is in devices for medical, sensor and prosthetic applications. Worldwide energy demand is increasing as the population grows and the standard of living in developing countries improves. Some studies estimate as much as 20% of annual energy usage is consumed by lighting. Improvements are being made in lightweight, flexible, rugged panels that use organic light emitting diodes (OLEDs), which are particularly useful in developing regions with limited energy availability and harsh environments. Displays also benefit from more efficient materials as well as the lighter weight and ruggedness enabled by flexible substrates. Displays may require different emission characteristics compared with solid-state lighting. Some display technologies use a white OLED (WOLED) backlight with a color filter, but these are more complex and less efficient than displays that use separate emissive materials that produce the saturated colors needed to reproduce the entire color gamut. Saturated colors require narrow-band emitters. Full-color OLED displays up to and including television size are now commercially available from several suppliers, but research continues to develop more efficient and more stable materials. This research program investigates several topics relevant to solid-state lighting and display applications. One project is development of a device structure to optimize performance of a new stable Pt-based red emitter developed in Prof Jian Li's group. Another project investigates new Pt-based red, green and blue emitters for lighting applications and compares a red/blue structure with a red/green/blue structure to produce light with high color rendering index. Another part of this work describes the fabrication of a 14.7" diagonal full color active-matrix OLED display on plastic substrate. The backplanes were designed and fabricated in the ASU Flexible Display Center and required significant engineering to develop; a discussion of that process is also included. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2017

2 pp. / Drip irrigation is the slow, measured application of waer through devices called emitters. Now a wide variety of quality products has been developed to make drip irrigation reliable and easy.

This thesis is concerned with the characterisation, fabrication and testing of devices capable of generating and detecting terahertz (THz) radiation. Such devices are based on semiconductor photoconductors grown under low temperature (LT) conditions using the technique of Molecular Beam Epitaxy (MBE). The absorption of a pulsed or continuous wave (CW) signal by these structures in conjunction with the presence of an electric field generates photocurrent, which is fed into an antenna structure fabricated on the surface of the active layers. As a result of such a sequence, a THz signal is generated and radiated from the substrate side into free space. Therefore, the efficiency of the devices is determined by the characteristics of the photoconductors and the geometry of the designed antenna structures. The desired material characteristics are high absorption at the corresponding illumination wavelength, high dark resistivity, high electron mobility and sub picosecond carrier lifetime. The determination of these characteristics for all the structures grown in this work composes the characterisation part of the thesis. The fabrication part comprises of the design of several antenna structures with various geometrical characteristics, while the testing part consists of their evaluation as THz sources and detectors in a time-domain spectroscopy (TDS) system under pulsed excitation. To date, THz devices based on low temperature grown GaAs (LT-GaAs) photoconductors have been reported to be the most efficient. However, their operational wavelength, at 800 nm, requires very expensive and complex components spurring interests in solutions consisting of devices operating at longer wavelengths, where cheaper and simpler components exist. The most desirable and practical operational wavelength is the telecommunication one at 1.55 μm. Thus, the biggest challenge is the development of efficient devices operating at this illumination wavelength. In this work, devices operating at the very important wavelength of 1.55 μm as well as at the wavelengths of 1 μm and 800 nm are presented. The key findings for the long wavelength devices (1.55 μm) demonstrate photoconductors with ultrafast carrier lifetimes (~ 120 fs), high resistivity (> 105 Ω / sq), high mobility (> 1000 cm2 / Vs) and system responses with spectral range up to 3 THz and power-to-noise ratio of 60 dB. These characteristics are among the best ever reported for such material systems, making them efficient THz devices for various optoelectronic applications, especially for telecommunication laser-driven CW THz systems.