Date of Award

Spring 1-1-2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

First Advisor

Noel A. Clark

Second Advisor

Joseph E. Maclennan

Third Advisor

David M. Walba

Fourth Advisor

Charles T. Rogers

Fifth Advisor

Matthew A. Glaser

Abstract

The electro optical response of liquid crystalline materials while displaying anisotropic properties, has led to numerous optical applications.

A retro-reflecting modulator for optical communication systems using a high numerical aperture objective lens and a planar aligned nematic liquid crystal electrooptic cell that tunes the optical path length in the liquid crystal layer as a function of applied voltage has been developed. The field-induced phase shift varies the dependence of liquid crystal layer reflectivity in angle of incidence θ. This dependence can be studied in-situ by performing positional scan, z, along the axis of symmetry of the lens scan, focusing the light with an aberrative lens such that angle of incidence depends on z and measuring the reflectivity in the far field. These data show that a low reflected state can be achieved when liquid crystal thickness such that destructive interference with paraxial angle of incidence with θ ≈ 0 and high field "hometropic" orientation.

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