Fast Response Dual Frequency Liquid Crystal Materials,
2010
University of Central Florida
Fast Response Dual Frequency Liquid Crystal Materials, Qiong Song
Electronic Theses and Dissertations
Dual frequency liquid crystal (DFLC) exhibits a positive dielectric anisotropy at low frequencies and negative dielectric anisotropy at high frequencies. The frequency where dielectric anisotropy is zero is called crossover frequency. DFLC can achieve fast rise time and fast decay time with the assistance of applied voltage. However, one drawback of DFLC is that it has dielectric heating effect when driven at a high frequency. Thus, the first part of this dissertation is to develop low crossover frequency DFLC materials. The dielectric relaxation and physical properties of some single- and double-ester compounds were investigated. Experimental results indicate that the double-ester …
Experimental And Theoretical Approaches To Characterization Of Electronic Nonlinearities In Direct-Gap Semiconductors,
2010
University of Central Florida
Experimental And Theoretical Approaches To Characterization Of Electronic Nonlinearities In Direct-Gap Semiconductors, Claudiu Cirloganu
Electronic Theses and Dissertations
The general goal of this dissertation is to provide a comprehensive description of the limitations of established theories on bound electronic nonlinearities in direct-gap semiconductors by performing various experiments on wide and narrow bandgap semiconductors along with developing theoretical models. Nondegenerate two-photon absorption (2PA) is studied in several semiconductors showing orders of magnitude enhancement over the degenerate counterpart. In addition, three-photon absorption (3PA) is studied in ZnSe and other semiconductors and a new theory using a Kane 4-band model is developed which fits new data well. Finally, the narrow gap semiconductor InSb is studied with regard to multiphoton absorption, free-carrier …
Silicon-Sensitized Erbium Excitation In Silicon-Rich Silica For Integrated Photonics,
2010
University of Central Florida
Silicon-Sensitized Erbium Excitation In Silicon-Rich Silica For Integrated Photonics, Oleksandr Savchyn
Electronic Theses and Dissertations
It is widely accepted that the continued increase of processor performance requires at least partial replacement of electronic interconnects with their photonic counterparts. The implementation of optical interconnects requires the realization of a silicon-based light source, which is challenging task due to the low emission efficiency of silicon. One of the main approaches to address this challenge is the use of doping of silicon based matrices with optical centers, including erbium ions. Erbium ions incorporated in various hosts assume the trivalent state (Er3+) and demonstrate a transition at 1.54 μm, coinciding with optical transmission windows in both silicon and silica. …
A Wearable Head-Mounted Projection Display,
2010
University of Central Florida
A Wearable Head-Mounted Projection Display, Ricardo F. Martins
Electronic Theses and Dissertations
Conventional head-mounted projection displays (HMPDs) contain of a pair of miniature projection lenses, beamsplitters, and miniature displays mounted on the helmet, as well as a retro-reflective screen placed strategically in the environment. We have extened the HMPD technology integrating the screen into a fully mobile embodiment. Some initial efforts of demonstrating this technology has been captured followed by an investigation of the diffraction effects versus image degradation caused by integrating the retro-reflective screen within the HMPD. The key contribution of this research is the conception and development of a mobileHMPD (M-HMPD). We have included an extensive analysis of macro- and …
Near-Field Radiative Transfer: Thermal Radiation, Thermophotovoltaic Power Generation And Optical Characterization,
2010
University of Kentucky
Near-Field Radiative Transfer: Thermal Radiation, Thermophotovoltaic Power Generation And Optical Characterization, Mathieu Francoeur
University of Kentucky Doctoral Dissertations
This dissertation focuses on near-field radiative transfer, which can be defined as the discipline concerned with energy transfer via electromagnetic waves at sub-wavelength distances. Three specific subjects related to this discipline are investigated, namely nearfield thermal radiation, nanoscale-gap thermophotovoltaic (nano-TPV) power generation and optical characterization. An algorithm for the solution of near-field thermal radiation problems in one-dimensional layered media is developed, and several tests are performed showing the accuracy, consistency and versatility of the procedure. The possibility of tuning near-field radiative heat transfer via thin films supporting surface phononpolaritons (SPhPs) in the infrared is afterwards investigated via the computation of …
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doped Fiber Amplifier.,
2010
Universiti Malaya
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doped Fiber Amplifier., Sharifeh Shahi
Student Works (2010-2019)
A thorough study on Bismuth-based Erbium-doped fiber (Bi-EDF) is presented for wide-band amplifiers and multi-wavelength fiber laser applications. This fiber allows high Erbium ions concentration to be doped without a significant concentration quenching effect. The high refractive index characteristic in the Bi-EDF has broadened the emission spectrum of Erbium ions to achieve a broader gain spectrum up to extended L-band region compared to normal silica-based Erbium-doped fiber (EDF). The Bi-EDFA performances have been investigated in terms of power conversion efficiency (PCE), quantum conversion efficiency (QCE), gain and noise figure. The highest QCE and PCE for a 215 cm long of …
