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The effects of a squeezed vacuum on absorptive optical bistability (AOB) are calculated using the different relaxation rate approximation for in-quadrature and in-phase components of a two-level system developed by Gardiner. An expression for the complex absorption coefficient is developed, and the result applied to the AOB equation for the unidirectional ring cavity. We find a significant degradation of bistability for values of the in-quadrature decay constant less than or equal to approximately.5 of the in-phase decay constant. Effects of detuning and relative phase of the pump field to the squeezed vacuum field are also examined.

The fundamental limitations on the operation of optical bistable devices in a ring cavity and in GaAs etalons are investigated. Experimental results of spontaneous transitions due to shot noise fluctuations are found in good agreement with various "ladder" models, if one allows the counting rates to vary accordingly. Stability analysis for two-photon homogeneously broadened media reveals single-wavelength instabilities for the laser but not for absorptive optical bistability. Appreciable regions of sidemode gain exist for both problems allowing for multiwavelength instabilities to occur. GaAs bistable devices show attractive features such as low power and high speed at room temperature for optical processing. However, experimental evidence in GaAs confirm the computer simulations of bistability that cavity losses, due to unsaturable background absorption, limit the switching power at room temperature. Methods to overcome the different limitations in GaAs devices toward parallel computation are then addressed from a system approach.

Nonlinear optical transverse effects, which arise from the interaction of a Gaussian beam with a nonlinear medium, are discussed. They are cw on-resonance enhancement (CORE), cw off-resonance rings, crosstalk, intracavity phase switching, self-defocusing of a bistable etalon, and thin-sample-encoding (TSE) self-lensing (i.e., self-focusing or self-defocusing) bistability and instabilities. CORE is the enhancement of the on-axis intensity of an on-resonance laser beam in a two-level medium. We report the first observation of CORE using sodium vapor. Cw off-resonance rings, resulting from a pure phase encoding or from simultaneous phase and amplitude encodings, are observed using sodium vapor. These rings have been observed many time before, but we have made the first careful comparison with numerical calculations. Parallel operation and external switching are two crucial themes for the application of bistable optical devices (BODs). For parallel operation, crosstalk between nearby BODs on the same etalon due to diffraction coupling may need to be avoided. Minimum separations needed to ensure independent operation are computed. For external switching, intracavity phase switching using a plane-wave input can switch on (or off) a BOD using an external pulse. The validity of this concept for a Gaussian input is numerically simulated. Self-defocusing effects, resulting in some interesting effects in the transverse bistable loops, are observed using a GaAs-GaAlAs bistable etalon. The results are confirmed by numerical simulations. TSE self-lensing bistability is observed using a short sodium cell and a single mirror. TSE self-lensing bistability results from an enhancement in the feedback via self-lensing of the beam. The lack of an optical resonator and the use of a thin medium make TSE setup a good candidate to study the Ikeda instability. We report the first observation of the Ikeda instability in this all-optical passive system using a cw input. Numerical simulations show a rich bifurcation sequence not yet fully studied experimentally.

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Thesis (Ph. D.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 184-201). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9998026.

Passive intrinsic bistability is of great interest. Our Fabry-Perot interference filters exhibit bistability due to a temperature dependent refractive index. Operating across the entire viable spectrum permits wide application to the demonstration and development of concepts for optical computing. Thermal evaporation of zinc sulfide and chiolite is used to produce Fabry-Perot interference filters. The effect of the thickness of the spacer, and reflectivities of the mirrors, on the nonlinear characteristics of these devices is investigated. The mathematic description of these etalon's linear, as well as their nonlinear, behavior is presented. The experimental apparatus is described. Measured values of the minimum critical detuning and minimum observed power are presented.

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