Matching Items (161)
Description
The Mormon Plan of Salvation explains that people originate in a heavenly state and are sent to Earth in a physical form, where they aspire to lead good lives and gain wisdom in order to reach glory in the afterlife. The dance piece "From There to Here to There: Whose Journey is it Anyway?" explores each stage in the Plan of Salvation at a different location, requiring dancers and audience to travel both metaphorically and physically. The piece incorporates several kinds of journeys: the collective journey of humankind based on the Plan of Salvation, the dancers' own journeys, and audience's journey as they watch the piece, and my journey as an artist. In the process of making this piece, I refined my identity as a 21st century Mormon artist interested in conveying religious messages through the traditionally secular art form of postmodern dance.
ContributorsFrost, Randi (Author) / Kaplan, Robert (Thesis advisor) / Daughtrey, Doe (Committee member) / Schupp, Karen (Committee member) / Arizona State University (Publisher)
Created2011
Description
Dual-wavelength laser sources have various existing and potential applications in wavelength division multiplexing, differential techniques in spectroscopy for chemical sensing, multiple-wavelength interferometry, terahertz-wave generation, microelectromechanical systems, and microfluidic lab-on-chip systems. In the drive for ever smaller and increasingly mobile electronic devices, dual-wavelength coherent light output from a single semiconductor laser diode would enable further advances and deployment of these technologies. The output of conventional laser diodes is however limited to a single wavelength band with a few subsequent lasing modes depending on the device design. This thesis investigates a novel semiconductor laser device design with a single cavity waveguide capable of dual-wavelength laser output with large spectral separation. The novel dual-wavelength semiconductor laser diode uses two shorter- and longer-wavelength active regions that have separate electron and hole quasi-Fermi energy levels and carrier distributions. The shorter-wavelength active region is based on electrical injection as in conventional laser diodes, and the longer-wavelength active region is then pumped optically by the internal optical field of the shorter-wavelength laser mode, resulting in stable dual-wavelength laser emission at two different wavelengths quite far apart. Different designs of the device are studied using a theoretical model developed in this work to describe the internal optical pumping scheme. The carrier transport and separation of the quasi-Fermi distributions are then modeled using a software package that solves Poisson's equation and the continuity equations to simulate semiconductor devices. Three different designs are grown using molecular beam epitaxy, and broad-area-contact laser diodes are processed using conventional methods. The modeling and experimental results of the first generation design indicate that the optical confinement factor of the longer-wavelength active region is a critical element in realizing dual-wavelength laser output. The modeling predicts lower laser thresholds for the second and third generation designs; however, the experimental results of the second and third generation devices confirm challenges related to the epitaxial growth of the structures in eventually demonstrating dual-wavelength laser output.
ContributorsGreen, Benjamin C (Author) / Zhang, Yong-Hang (Thesis advisor) / Ning, Cun-Zheng (Committee member) / Tao, Nongjian (Committee member) / Roedel, Ronald J (Committee member) / Arizona State University (Publisher)
Created2011
Description
The purpose of my creative research was to analyze my choreographic process and answer the research question: how will implementing somatic principles impact my choreographic process? In determining the impact I analyzed the use of choreographic approaches that bring proprioceptive awareness to interdisciplinary somatic themes of bodily systems, sensing, connectivity, initiation and sequencing. These somatic themes were utilized in movement invention and exploration as well as the structuring and performance of my choreography. Additionally, the research involved clarifying my role as a choreographer and my relationship to the dancers in my work. My creative research occurred in three choreographic phases and resulted in the production of B.O.D.I.E.S performed in three consecutive sections titled Discovery, Exploration, and Identity November 5-7, 2010. B.O.D.I.E.S demonstrates how somatics will lead to greater movement possibilities and dynamic range to explore in the craft of dance making.
ContributorsHillerby, Rebecca Blair (Author) / Schupp, Karen (Thesis advisor) / Roses-Thema, Cynthia (Thesis advisor) / Coleman, Grisha (Committee member) / Arizona State University (Publisher)
Created2011
Description
The long wavelength infrared region (LWIR) and mid wavelength infrared region (MWIR) are of great interest as detection in this region offers a wide range of real time applications. Optoelectronic devices operating in the LWIR and MWIR region offer potential applications such as; optical gas sensing, free-space optical communications, infrared counter-measures, biomedical and thermal imaging etc. HgCdTe is a prominent narrow bandgap material that operates in the LWIR region. The focus of this research work is to simulate and analyze the characteristics of a Hg1-xCdxTe photodetector. To achieve this, the tool `OPTODET' has been developed, where various device parameters can be varied and the resultant output can be analyzed. By the study of output characteristics in response to various changes in device parameters will allow users to understand the considerations that must be made in order to reach the optimum working point of an infrared detector. The tool which has been developed is a 1-D drift diffusion based simulator which solves the 1-D Poisson equation to determine potentials and utilizes the results of the 1-D electron and hole continuity equations to determine current. Parameters such as absorption co-efficient, quantum efficiency, dark current, noise, Transit time and detectivity can be simulated. All major recombination mechanisms such as SRH, Radiative and Auger recombination have been considered. Effects of band to band tunnelling have also been considered to correctly model the dark current characteristics.
ContributorsMuralidharan, Pradyumna (Author) / Vasileska, Dragica (Thesis advisor) / Wijewarnasuriya, Priyalal S. (Committee member) / Zhang, Yong-Hang (Committee member) / Arizona State University (Publisher)
Created2011
Description
MOVE was a choreographic project that investigated content in conjunction with the creative process. The yearlong collaborative creative process utilized improvisational and compositional experiments to research the movement potential of the human body, as well as movement's ability to be an emotional catalyst. Multiple showings were held to receive feedback from a variety of viewers. Production elements were designed in conjunction with the development of the evening-length dance work. As a result of discussion and research, several process-revealing sections were created to provide clear relationships between pedestrian/daily functional movement and technical movement. Each section within MOVE addressed movement as an emotional catalyst, resulting in a variety of emotional textures. The sections were placed in a non-linear structure in order for the audience to have the space to create their own connections between concepts. Community was developed in rehearsal via touch/weight sharing, and translated to the performance of MOVE via a communal, instinctive approach to the performance of the work. Community was also created between the movers and the audience via the design of the performance space. The production elements all revolved around the human body, and offered different viewpoints into various body parts. The choreographer, designers, and movers all participated in the creation of the production elements, resulting in a clear understanding of MOVE by the entire community involved. The overall creation, presentation, and reflection of MOVE was a view into the choreographer's growth as a dance artist, and her values of people and movement.
ContributorsPeterson, Britta Joy (Author) / Fitzgerald, Mary (Thesis advisor) / Schupp, Karen (Committee member) / Mcneal Hunt, Diane (Committee member) / Arizona State University (Publisher)
Created2013
Description
A dual chamber molecular beam epitaxy (MBE) system was rebuilt for the growth of 6.1 Angstrom II-VI and III-V compound semiconductor materials that are to be used in novel optoelectronic devices that take advantage of the nearly continuous bandgap availability between 0 eV and 3.4 eV. These devices include multijunction solar cells and multicolor detectors. The MBE system upgrade involved the conversion of a former III-V chamber for II-VI growth. This required intensive cleaning of the chamber and components to prevent contamination. Special features including valved II-VI sources and the addition of a cold trap allowed for the full system to be baked to 200 degrees Celsius to improve vacuum conditions and reduce background impurity concentrations in epilayers. After the conversion, the system was carefully calibrated and optimized for the growth of ZnSe and ZnTe on GaAs (001) substrates. Material quality was assessed using X-ray diffraction rocking curves. ZnSe layers displayed a trend of improving quality with decreasing growth temperature reaching a minimum full-width half-maximum (FWHM) of 113 arcsec at 278 degrees Celsius. ZnTe epilayer quality increased with growth temperature under Zn rich conditions attaining a FWHM of 84 arcsec at 440 degrees Celsius. RHEED oscillations were successfully observed and used to obtain growth rate in situ for varying flux and temperature levels. For a fixed flux ratio, growth rate decreased with growth temperature as the desorption rate increased. A directly proportional dependence of growth rate on Te flux was observed for Zn rich growth. Furthermore, a method for determining the flux ratio necessary for attaining the stoichiometric condition was demonstrated.
ContributorsDettlaff, W. Hank G (Author) / Zhang, Yong-Hang (Thesis advisor) / Vasileska, Dragica (Committee member) / Johnson, Shane (Committee member) / Arizona State University (Publisher)
Created2012
Description
A Sense Of is a performance-based work that addresses the effects of the transformation of space, time, and energy through the various sensory modes. The work is an invitation to the artist's perspective of the world, which is combined with the performers' creative voices and interpretations of the artist's explorations into sensory awareness. The movement installation entitled A Sense Of was presented in November 2011. This document presents an overview of the project. It addresses relevant literature, examines the creative process used in the work, and provides an analysis of the project as a whole.
ContributorsUllom, Kathryn (Author) / Standley, Eileen (Thesis advisor) / Fitzgerald, Mary (Committee member) / Schupp, Karen (Committee member) / Klett, Mark (Committee member) / Arizona State University (Publisher)
Created2012
Description
This thesis summarizes the research work carried out on design, modeling and simulation of semiconductor nanophotonic devices. The research includes design of nanowire (NW) lasers, modeling of active plasmonic waveguides, design of plasmonic nano-lasers, and design of all-semiconductor plasmonic systems. For the NW part, a comparative study of electrical injection in the longitudinal p-i-n and coaxial p-n core-shell NWs was performed. It is found that high density carriers can be efficiently injected into and confined in the core-shell structure. The required bias voltage and doping concentrations in the core-shell structure are smaller than those in the longitudinal p-i-n structure. A new device structure with core-shell configuration at the p and n contact regions for electrically driven single NW laser was proposed. Through a comprehensive design trade-off between threshold gain and threshold voltage, room temperature lasing has been proved in the laser with low threshold current and large output efficiency. For the plasmonic part, the propagation of surface plasmon polariton (SPP) in a metal-semiconductor-metal structure where semiconductor is highly excited to have an optical gain was investigated. It is shown that near the resonance the SPP mode experiences an unexpected giant modal gain that is 1000 times of the material gain in the semiconductor and the corresponding confinement factor is as high as 105. The physical origin of the giant modal gain is the slowing down of the average energy propagation in the structure. Secondly, SPP modes lasing in a metal-insulator-semiconductor multi-layer structure was investigated. It is shown that the lasing threshold can be reduced by structural optimization. A specific design example was optimized using AlGaAs/GaAs/AlGaAs single quantum well sandwiched between silver layers. This cavity has a physical volume of 1.5×10-4 λ03 which is the smallest nanolaser reported so far. Finally, the all-semiconductor based plasmonics was studied. It is found that InAs is superior to other common semiconductors for plasmonic application in mid-infrared range. A plasmonic system made of InAs, GaSb and AlSb layers, consisting of a plasmonic source, waveguide and detector was proposed. This on-chip integrated system is realizable in a single epitaxial growth process.
ContributorsLi, Debin (Author) / Ning, Cun-Zheng (Thesis advisor) / Zhang, Yong-Hang (Committee member) / Balanis, Constantine A (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2012
Description
Infrared photodetectors, used in applications for sensing and imaging, such as military target recognition, chemical/gas detection, and night vision enhancement, are predominantly comprised of an expensive II-VI material, HgCdTe. III-V type-II superlattices (SLs) have been studied as viable alternatives for HgCdTe due to the SL advantages over HgCdTe: greater control of the alloy composition, resulting in more uniform materials and cutoff wavelengths across the wafer; stronger bonds and structural stability; less expensive substrates, i.e., GaSb; mature III-V growth and processing technologies; lower band-to-band tunneling due to larger electron effective masses; and reduced Auger recombination enabling operation at higher temperatures and longer wavelengths. However, the dark current of InAs/Ga1-xInxSb SL detectors is higher than that of HgCdTe detectors and limited by Shockley-Read-Hall (SRH) recombination rather than Auger recombination. This dissertation work focuses on InAs/InAs1-xSbx SLs, another promising alternative for infrared laser and detector applications due to possible lower SRH recombination and the absence of gallium, which simplifies the SL interfaces and growth processes. InAs/InAs1-xSbx SLs strain-balanced to GaSb substrates were designed for the mid- and long-wavelength infrared (MWIR and LWIR) spectral ranges and were grown using MOCVD and MBE by various groups. Detailed characterization using high-resolution x-ray diffraction, atomic force microscopy, photoluminescence (PL), and photoconductance revealed the excellent structural and optical properties of the MBE materials. Two key material parameters were studied in detail: the valence band offset (VBO) and minority carrier lifetime. The VBO between InAs and InAs1-xSbx strained on GaSb with x = 0.28 - 0.41 was best described by Qv = ÄEv/ÄEg = 1.75 ± 0.03. Time-resolved PL experiments on a LWIR SL revealed a lifetime of 412 ns at 77 K, one order of magnitude greater than that of InAs/Ga1-xInxSb LWIR SLs due to less SRH recombination. MWIR SLs also had 100's of ns lifetimes that were dominated by radiative recombination due to shorter periods and larger wave function overlaps. These results allow InAs/InAs1-xSbx SLs to be designed for LWIR photodetectors with minority carrier lifetimes approaching those of HgCdTe, lower dark currents, and higher operating temperatures.
ContributorsSteenbergen, Elizabeth H (Author) / Zhang, Yong-Hang (Thesis advisor) / Brown, Gail J. (Committee member) / Vasileska, Dragica (Committee member) / Johnson, Shane R. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Nanowires (NWs) have attracted many interests due to their advance in synthesis and their unique structural, electrical and optical properties. NWs have been realized as promising candidates for future photonic platforms. In this work, erbium chloride silicate (ECS), CdS and CdSSe NWs growth by vapor-liquid-solid mechanism and their characterization were demonstrated. In the ECS NWs part, systematic experiments were performed to investigate the relation between growth temperature and NWs structure. Scanning electron microscopy, Raman spectroscopy, X-ray diffraction and photoluminescence characterization were used to study the NWs morphology, crystal quality and optical properties. At low growth temperature, there was strong Si Raman signal observed indicating ECS NWs have Si core. At high growth temperature, the excess Si signal was disappeared and the NWs showed better crystal quality and optical properties. The growth temperature is the key parameter that will induce the transition from Si/ECS core-shell NWs structure to solid ECS NWs. With the merits of high Er concentration and long PL lifetime, ECS NWs can serve as optical gain material with emission at 1.5 μm for communications and amplifiers. In the CdS, CdSSe NWs part, the band gap engineering of CdSSe NWs with spatial composition tuning along single NWs were demonstrated. The first step of realizing CdSSe NWs was the controlled growth of CdS NWs. It showed that overall pressure would largely affect the lengths of the CdS NWs. NWs with longer length can be obtained at higher pressure. Then, based on CdS NWs growth and by adding CdSe step by step, composition graded CdSSe alloy NWs were successfully synthesized. The temperature control over the source vapor concentration plays the key role for the growth.
ContributorsNing, Hao (Author) / Ning, Cunzheng (Thesis advisor) / Yu, Hongbin (Committee member) / Zhang, Yong-Hang (Committee member) / Arizona State University (Publisher)
Created2012