Second harmonic generation in optical fibers.
dc.contributor.author | Kamal, Avais | en_US |
dc.contributor.advisor | Weinberger, Doreen A. | en_US |
dc.date.accessioned | 2014-02-24T16:29:51Z | |
dc.date.available | 2014-02-24T16:29:51Z | |
dc.date.issued | 1991 | en_US |
dc.identifier.other | (UMI)AAI9208574 | en_US |
dc.identifier.uri | http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:9208574 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/105724 | |
dc.description.abstract | Discovery of photo-induced, self-phase-matched second-harmonic generation (SHG) in fused silica has been both exciting and intriguing. An understanding of the physical mechanisms, which destroy the centro-symmetry of fused silica and organize the nonlinearity for quasi-phasematching has remained a challenge. The purpose of this study was to investigate these mechanisms. In particular, spatially resolved Raman spectroscopy was applied to demonstrate a spatial periodicity, associated with the induced $\chi\sp{(2)}$, in the material properties of the fiber. Electro-optic sampling was used for the first time to measure volume polarizations. An internal field of 10$\sp4$ V/cm was measured. An internal field as large as this supports the view that the $\chi\sp{(2)}$ is induced by an internal field. A material modification which enhances the efficiency of SHG was achieved using gamma-ray irradiation. A microscopic picture based on oxygen vacancies has been proposed to explain the enhancement in efficiency. According to this picture, oxygen vacancies are a necessary ingredient for the self-organization process. A detailed study of the dynamics of $\chi\sp{(2)}$ gratings was also conducted. Results of this study show that the initial growth rate of $\chi\sp{(2)}$, which is linear in time, has the following dependence on the seed-second harmonic and IR fields:$$\rm {d \chi \sp{(2)} \over dt} \propto\left(\vert E\sbsp{cond}{2\omega} \vert\sp2\right)\sp{1.48 \pm 0.2} \left(\vert E\sbsp{cond}{\omega} \vert \sp2\right)\sp{0.9 \pm .2}.$$These results suggest that the driving mechanism for self-organization is an interference between a two-photon (2$\omega$, 2$\omega$) and a three-photon (2$\omega$, $\omega$, $\omega$) ionization processes. A model based on this type of interference has been explored. This model is in qualitative agreement with some of our experimental results. | en_US |
dc.format.extent | 126 p. | en_US |
dc.subject | Engineering, Electronics and Electrical | en_US |
dc.title | Second harmonic generation in optical fibers. | en_US |
dc.type | Thesis | en_US |
dc.description.thesisdegreename | PhD | en_US |
dc.description.thesisdegreediscipline | Electrical Engineering | en_US |
dc.description.thesisdegreegrantor | University of Michigan, Horace H. Rackham School of Graduate Studies | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/105724/1/9208574.pdf | |
dc.description.filedescription | Description of 9208574.pdf : Restricted to UM users only. | en_US |
dc.owningcollname | Dissertations and Theses (Ph.D. and Master's) |
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