Dissertation/Thesis Abstract

Patterned Liquid Crystal Polymer Retarders, Polarizers, and Sources
by Myhre, Graham, Ph.D., The University of Arizona, 2012, 125; 3507362
Abstract (Summary)

Liquid crystals are traditionally aligned via a rubbed substrate. The rubbing creates anisotropic defects and strain in the material which provide an energetically favorable orientation for the liquid crystal (LC). This is a well-developed technology that is used in virtually all liquid crystal displays (LCDs). However, it is only capable of uniform alignment on a large planar substrate. This work utilizes a new class of photoalignment materials (PM) that replace the traditional buffing technique. PMs allow for patterned LC alignment using polarized photo-lithography. Further, instead of using a nematic liquid crystal, a UV curable liquid crystal polymer (LCP) is coated on this patterned alignment material. This generates a cured, aligned, and patterned thin film that has retardance and diattenuation if a dichroic dye is incorporated in the LCP. Using these materials and methods, retarders, polarizers, and polarized fluorescent sources are fabricated with dimensions as small as a few microns.

In addition to exploring the material and processing properties of the PM and LCP system, arrays of micropolarizer are fabricated for the construction of a prototype polarization camera, termed an imaging polarimeter. An imaging polarimeter is a device that measures not only the intensity but also the polarization state of a light field. My imaging polarimeter design incorporates a patterned LCP polarizer focal plane array (FPA) that is aligned and mounted to a charge-couple-device (CCD) image sensor. A polarizer FPA allows an individual pixel on a CCD sensor to detect a unique polarization state, such as a specific linear polarization orientation or right or left handed circular polarization. Neighboring pixels are designed to detect different states and each cluster can then estimate the incident polarization state. Results of a linear LCP polarimeter operating in the visible spectrum are presented.

Indexing (document details)
Advisor: Pau, Stanley
Commitee: Chipman, Russell A., Milster, Thomas D.
School: The University of Arizona
Department: Optical Sciences
School Location: United States -- Arizona
Source: DAI-B 73/09(E), Dissertation Abstracts International
Subjects: Optics, Materials science
Keywords: Dichroic dye, Focal plane arrays, Liquid crystals, Photo alignment, Polarimeter, Polarized fluorescence
Publication Number: 3507362
ISBN: 9781267323491