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Type of Document	Dissertation
Author	Panotopoulos, George
URN	etd-04282003-142947
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-04282003-142947
Title	Holographic information systems
Degree	PhD
Option	Electrical Engineering
Advisory Committee	Advisor Name Title Demetri Psaltis Committee Member
Keywords	none
Date of Defense	2002-07-01
Availability	unrestricted
Abstract The goal of this work is to investigate the use of holographic techniques for information processing and transmission systems. Until recently information has been processed and transmitted mainly electronically. With the advent of optical fiber communications the monopoly of electronics has receded in the telecommunications field, but the domain of information processing is still dominated by electronic processors. This thesis follows a top-down approach to the design of processors that integrate both electronic and optical components. It begins with the design considerations of a compact, rapidly reconfigurable opto-electronic processor, which possesses an optical bus in addition to the traditional electronic bus. The optical bus takes advantage of the massive parallelism that is afforded by optics and can be coupled to a holographic digital memory, allowing rapid reconfiguration of the device. The capability of rapid reconfiguration gives rise to a new computational paradigm, where the reprogramming of the device can become part of the computation. We suggest additional applications of this processor, namely as a smart reading head for large scale holographic disk memories. Finally we present novel algorithms that were developed specifically to take advantage of the additional capabilities of our processor. The next section is concerned with the wavelength and angular tuning of strong volume holograms, both in the reflection and 90-degree geometries. Since photons have no charge, we need to rely on their wave properties to manipulate them, both for long-range transmission, such as telecommunications, and short-range transmission, such as on chip interconnects. In this section we investigate how volume holograms can be used to selectively redirect information bearing light beams. The final part of this thesis is concerned with material issues. Holographic recording of strong volume gratings is one of the most commonly used approaches, and photorefractive materials have a strong bearing on the overall performance of the final system. Two properties of iron doped lithium niobate are investigated, namely the dependence of absorption on temperature and the quadratic electro-optic coefficient. The former is crucial for the commonly used technique of thermal fixing, and the latter can become significant should we choose to use applied continuous fields to tune our gratings.
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