Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 48 for “"poling"”.
-
Microstructuring and domain-engineering of lithium niobate using combinations of light, etching and poling
… Device construction uses electric field poling of lithium niobate to create two parallel but oppositely oriented domains. When an electric field is applied across the interface between these domains a change in the refractive index of equal magnitude but of opposite sign is induced. If …
-
Multi-Scale Effects of Poling on Structure-Property Relationships in Lead Magnesium Niobate-Lead Titanate Single Crystals
… was revealed by XRD in the transmission mode. Poling increased the average significance of the superlattice, signifying a structural contribution to the super-structure. The effects of poling on domain and crystallographic structure, and on phase transformation behavior, are reported. The use …
-
Elimination of PZT thin film breakage caused by electric current arcing and intrinsic differential strains during poling
Historically, substrate breakage during the poling process has been responsible for a 2% yield loss for a contract manufacturer specializing in volume production of lead zirconate titatate (PZT) thin film devices. In this research, two major causes of poling breakage were identified. First, …
-
Fabrication and applications of zinc indiffused waveguides in periodically poled lithium niobate
… to optical testing. The factors affecting poling quality, such as crystal discrepancies from different suppliers, electrode materials, patterning quality, and mask design, are investigated and analysed systematically. In addition, back-switch poling methods (involving poling a sample …
-
Mapping the security arrangements for Khayelitsha's schools: what are the normative and functional outcomes of a nodal policing approach to poling school-based violence in Khayelitsha?
In light of the contextual realities of school violence, the aim of this paper is to provide an analytical map of the security arrangements at schools in a particular area, namely Khayelitsha. The question is not whether these arrangements are failing (as will be made clear by the evidence provided …
-
Nonlinear Microscopy for Materials Analysis and Clinical Pathology
… for visible-near infrared light, periodic poling of thin film lithium niobate (TFLN) was conducted. State-of-the-art poling for quasi phase matching was achieved via an iterative process. Devices were poled in a custom-built high voltage probing setup and imaged with a second harmonic …
-
Modification and processing of glass and glass with embedded silver nanoparticles
… for varying applications. These are: thermal poling of glass, electric field assisted dissolution of glass embedded with silver nanoparticles and the irradiation of glass embedded with silver nanoparticles. Each method will be adapted to present novel and widely applicable approaches to the …
-
Modification of glasses and optical waveguides using high electric fields
… field strength. The fundamental research on poling induced nonlinearity has been extended to investigate several compositions of Bi<sub>2</sub>O<sub>3</sub>ZnOB<sub>2</sub>O<sub>3</sub> glass systems, whose refractive index is measured to increase with the Bi<sub>2</sub>O<sub>3</sub> content. …
-
Low Loss Hybrid Waveguide Electric Field Sensor Based on Optical D-fiber
… sensitive to electric fields through corona poling. The typical corona poling process is not amenable to poling a polymer located in the fiber core. A method of poling conducive to an in-fiber device was developed and demonstrated. Using PMMA and DR1 for proof of concept, the operation of the …
-
Domain engineering techniques and devices in lithium niobate
… etch-rate as a function of time-delay following poling, was suggestive of small atomic displacements following poling, and was quantified by the evidenced shifts in six major Raman spectral peaks. The noticeable modifications in the etch-behaviour of undoped congruent z-cut lithium niobate by …
-
Polarization-induced transport in ferroelelctric organic field-effect transistors
… We have come up with new methods of electrical poling the dielectric layer to enhance FET performance as well as reduce gate leakage issues. We demonstrate the effect of polarization rotation in PVDF-TrFE on the performance of small-molecule-based organic FETs. The subthreshold swing and other …
-
Light-induced ferroelectric domain engineering in lithium niobate & lithium tantalate
… method of domain inversion is electric field poling, which suffers from several limitations such as a requirement for photolithography and high-voltage equipment, the formation of inhomogeneous electric fields, and a minimum domain size of micrometres. Through the use of directed laser light, …
-
Electro-optic polymer-based monolithic waveguide devices with multi-functions of amplification switching and modulation
… a thermal-setting EO polymer PU-FTC, both corona poling and contact poling were investigated. A novel domain-inversion poling technique was developed. We demonstrated an electro-optic modulator based on a 1x2 Y-branch directional waveguide coupler. The symmetric geometry of this coupler provides …
-
Development of non-linear waveguide devices for optical signal processing
Reported in this thesis are advances in glass poling, a technique which produces second-order optical nonlinearity in glass. Poling of glass has drawn much attention because frequency conversion and electro-optic modulation, operations which are typically restricted to crystals, becomes feasible in …
-
Self Assembling Phenylene Vinylene Materials and Devices
… activity was demonstrated without prior poling procedures. Upon poling the net polarization was enhanced and piezoelectric activities equal to that of quartz were observed. By applying both positive and negative fields a hysteresis was observed suggesting that these materials exhibit …
-
Electro-Optic Properties of Self-Assembled Non-Linear Optical Polymers
… and thus doesn't require electric field poling and does not decay with time. The self-assembly process is therefore shown to possess great potential for the fabrication of high-speed electro-optic modulators for commercial and military applications.
-
Domain Switching and Microcracking in Ferroelectric Single Crystals and Polycrystalline Ceramics
… depended strongly upon the applied field and the poling direction. Analysis showed that cracks extended along the place of maximum normal strain. Mechanisms for the intergranular fracture were investigated by the in-situ TEM technique. During electrical cycling, transient dielectric breakdown and …
-
Organic materials for second-order nonlinear optics: Approaches to optimizing and stabilizing nonlinear optical effects
… such as molecular relaxation, dipolar ordering, poling dynamics, and intermolecular forces in organic materials were investigated. A second objective has been to identify mechanisms to optimize and stabilize second harmonic generation (SHG) signals through materials processing techniques. This …
-
Photonic Properties of Self -Assembled Organic Materials: Supramolecular Films, and Nanoribbon -Templated Gels and Polymers
… and the nanoribbons are oriented along the poling field, suggested by TEM studies of ultramicrotomed samples. DRC gelation process disperses inorganic nanocrystals like ZnO, forming a stable nanocrystal-nanoribbon hybrid material. Similar electrophoresis occurs to the gel containing ZnO, …
-
The Epstein-Barr Virus-Encoded BHRF1 miRNAs Regulate Viral Gene Expression in Cis
<p>Epstein Barr virus (EBV), a γ-herpesvirus that latently infects over 90% of the adult population, is known to play a role in the development of both B cell and epithelial cell tumors. In a laboratory setting, transformation of primary B cells into lymphoblastoid cell lines (LCLs) is used to …
Page 1 of 3