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Type of Document	Dissertation
Author	Orlov, Sergei S.
URN	etd-06082005-110714
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-06082005-110714
Title	Holographic storage dynamics, phase conjugation, and nonlinear optics in photorefractive materials
Degree	PhD
Option	Electrical Engineering
Advisory Committee	Advisor Name Title Amnon Yariv Committee Chair Demetri Psaltis Committee Member Kerry J. Vahala Committee Member Pietro Perona Committee Member Thomas C. McGill Committee Member
Keywords	lithium niobate holographic data storage phase conjugation photorefractive materials holography
Date of Defense	1996-05-23
Availability	unrestricted
Abstract This thesis explores the application of photorefractive materials in two distinct areas: the holographic data storage and the dynamic nonlinear optical interactions. First, we have established that partial ferroelectric domain reversal in certain ferroelectric materials can be used to permanently fix the dynamic holographic gratings, and analyzed the interaction between the fixed and the dynamic components of a hologram. A comprehensive analysis of the storage temporal dynamics in photorefractive materials is further developed for the case of thermal ionic fixing. An experimental study of holographic storage dynamics in photorefractive lithium niobate revealed new features related to the ionic conductivity in this and similar materials. We established and developed techniques for long-lifetime and high-efficiency hologram fixing in the holographic data storage applications. We further analyze theoretically the impact of the recording response properties of different storage media (including photorefractive materials and photopolymers) and optical detection noise on the ultimate storage capacity of holographic memories. Second, the transverse properties of the photorefractive double phase conjugate mirror (DPCM) have been studied. We have established that the DPCM exhibits a sharp conjugation fidelity gain threshold which increases with image resolution, while the reflectivity is a smoothly varying function of nonlinear gain. The conjugation fidelity was found to degrade dramatically for unequal intensities ratio. The DPCM exhibits critical slowing down in the vicinity of the oscillation threshold. A two-dimensional coupled-modes perturbation analysis of the DPCM is introduced and its basic predictions are in a good qualitative agreement with the results of the experimental study. Finally, we analyze the nonlinear optical second harmonic generation in materials with strong photorefractivity. In the presence of strong self-phase modulation the phase matching conditions are modified and we found that in some cases this leads to a unique effect, namely, the nonlinear self-phase matching of optical nonlinear interaction. Strong photorefractive response manifests itself in two characteristic and very apparent manners; a large change in the conversion efficiency and self-defocusing of the generated second harmonic beam. We introduced a two-dimensional model of photorefractive effect and found its predictions to be in a good qualitative agreement with the observed transverse dynamics.
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