This thesis discusses nonlinear effects, such as modulation instability and solitons in nano-structured waveguides. The nanoscale optical waveguides have extremely small transverse dimensions, which can provide tight confinement of light. Therefore, by changing the waveguide geometry, the waveguide dispersion can be strongly altered. On the other hand, the confinement also enhances the nonlinear dispersion, allowing for nonlinear optical phenomena supported by dispersion of nonlinearity. The new models governing evolution of the amplitudes of components of the optical waves interacting in the waveguides are derived for continuous wave and pulse wave using perturbation expansion method. The new modulation instability condition is found, as we take into account the dispersion of nonlinearity which is enhanced through a strong variation of the modal profile with the wavelength of light in sub-wavelength waveguides. We demonstrate that this dispersion of nonlinearity can lead to the modulation instability in the regime of normal group velocity dispersion through the mechanism independent from higher order dispersions of linear waves for continuous wave. We address that the new mechanism highly associated with dispersion of nonlinearity in sub-wavelength semiconductor waveguide induces the modulation instability in picsecond regime together with the cascaded generation of higher-order sidebands. The impact of the dispersion of nonlinearity on spectral broadening of short pulses in a silicon waveguide also is considered. We study the temporal evolutions of fundamental and one-ring solitary waves with phase dislocation in dielectric-metal-dielectric waveguides with PT-symmetry and numerically analyze the properties of these nonlinear localized modes and, In particular, reveal different scenarios of their instability.

Thesis (Ph. D.)--Washington State University, May 2007. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 130-138).

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Synthesis and physical characterizations of a novel class of zwitterionic organic chromophores were carried out. A series of tetracyanoquinodimethane (TCNQ) derivatives was prepared from reactions with primary and secondary amines. By modifications of the structure it was hoped to optimize their nonlinear properties. The newly synthesized organic chromophores were highly polar, zwitterionic and transparent at wavelengths above 600nm, which is a requirement for waveguide devices at 650nm. The molecular dipole moments were determined experimentally and theoretically. The experimental dipole moments and the theoretical dipole moments were found to be in agreement. The nonlinear optical properties of the new compounds were studied using the Kurtz powder technique. Large second harmonic generation was observed from 7-(2,6, dimethylmorpholino)-7-(4-methylpiperidine)- 8,8-dicyanoquinomethane (25 times urea) as a result of the noncentrosymmetric crystal lattice (P2(_1)2(_1)2(_1)). A large twist between the donor moieties and the benzene ring was found from the crystallographic data, and compared with a theoretical model using an ab initio calculation. Strong fluorescence was observed in the solid states and glass forming solvents at low temperatures. An increase of the quantum yields as a function of viscosity was observed due to the constraining effect of the environment. Variations in the quantum yields from chromophore doped polymeric matrices such as PMMA at room temperature and at low temperature are attributed to the different "free volume" of the polymeric matrices. Possible mechanisms for the emission process in either viscous or non-viscous media are proposed. Photodegradation in solution was observed for illumination by a white light source. In parallel studies photodegradation in PMMA films was observed both in air and under vacuum. A possible photodegradation mechanism via free radicals, compatible with these experimental observations is suggested.

Bibliography: leaves 220-230. / iv, 230, [25] leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis performs a modeling study on a number of sterically constrained aryl-alkyne type systems with the results being used to guide subsequent synthetic efforts. Disulfide, silylene, stannyl, oxalate and 1,2-dioxaethyl and 1,3-dioxapropyl linkages are investigated as candidates to constrain the rotation of the tolane substructure. A preliminary Z-scan experiment is developed and is demonstrated as being able to detect optical nonliniarities. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1997?

Copies of author's previously published works inserted. / Bibliography: p. 119-127. / 12, 127, [8], 35 p., [3] leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis demonstrates the combined use of stimulated Brillouin scattering (SBS) for aberration correction, auto alignment and pulse compression as an ideal technology for studies of nonlinear optical processes, in particular nonlinear optical scattering (NLS). / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1998

Thesis (Ph.D.) -- University of Adelaide, Dept. of Physics and Mathematical Physics, 1998. / Copies of author's previously published works inserted. Bibliography: p. 119-127.