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Full-Text Articles in Physics

Modifications To A Cavity Ringdown Spectrometer To Improve Data Acquisition Rates, Gregory Alan Bostrom Mar 2015

Modifications To A Cavity Ringdown Spectrometer To Improve Data Acquisition Rates, Gregory Alan Bostrom

Dissertations and Theses

Cavity ringdown spectroscopy (CRDS) makes use of light retention in an optical cavity to enhance the sensitivity to absorption or extinction of light from a sample inside the cavity. When light entering the cavity is stopped, the output is an exponential decay with a decay constant that can be used to determine the quantity of the analyte if the extinction or absorption coefficient is known. The precision of the CRDS is dependent on the rate at which the system it acquires and processes ringdowns, assuming randomly distributed errors. We have demonstrated a CRDS system with a ringdown acquisition rate of …


Optical Propagation Of Self-Sustaining Wavefronts And Nonlinear Dynamics In Parabolic Multimode Fibers, Matthew Mills Jan 2015

Optical Propagation Of Self-Sustaining Wavefronts And Nonlinear Dynamics In Parabolic Multimode Fibers, Matthew Mills

Electronic Theses and Dissertations

The aim of this thesis is to introduce my work which has generally been focused on optical wavefronts that have the unusual property of resisting commonplace phenomena such as diffraction and dispersion. Interestingly, these special beams are found both in linear and nonlinear situations. For example, in the linear regime, localized spatio-temporal waves which resemble the spherical harmonic symmetries of the hydrogen quantum orbitals can simultaneously negotiate both diffractive and dispersive effects. In the nonlinear regime, dressed optical filaments can be arranged to propagate multi-photon produced plasma channels orders of magnitude longer than expected. The first portion of this dissertation …


Exchange Mechanisms In Macroscopic Ordered Organic Magnetic Semiconductors, Naveen Rawat Jan 2015

Exchange Mechanisms In Macroscopic Ordered Organic Magnetic Semiconductors, Naveen Rawat

Graduate College Dissertations and Theses

Small molecule organic semiconductors such as phthalocyanines and their derivatives represent a very interesting alternative to inorganic semiconductor materials for the development of flexible electronic devices such as organic thin field effect transistors, organic Light Emitting Diodes and photo-voltaic cells. Phthalocyanine molecules can easily accommodate a variety of metal atoms as well in the central core of the molecule, resulting in wide range of magnetic properties. Exploration of optical properties of organic crystalline semiconductors thin films is challenging due to sub-micron grain sizes and the presence of numerous structural defects, disorder and grain boundaries. However, this can be overcome by …