Dissertation
Light scattering in holographic polymer dispersed liquid crystals
Doctor of Philosophy (Ph.D.), Drexel University
May 2014
DOI:
https://doi.org/10.17918/etd-4564
Abstract
Holographic polymer dispersed liquid crystals (HPDLCs) are electro-optic devices that at the most basic level act as switchable color filters. The device is a Bragg grating structure made up of alternating layers of liquid crystal droplets and polymer planes. When no voltage is applied to the HPDLC, it reflects a narrow band of wavelengths, centered on the Bragg wavelength, and transmits other wavelengths of the incident light. When a voltage is applied, the device becomes transparent to the Bragg wavelength and transmits all of the incident light. HPDLCs have been used in a variety of different applications including remote sensing, hyperspectral imaging, switchable holographic optical elements, and displays. The light transmission and reflection properties of HPDLCs have been studied extensively, both experimentally and theoretically. However, the light scattering in HPDLCs has not been thoroughly studied even though it plays a large role in the device's performance in optical systems. This thesis will describe theoretical and experimental approaches to understanding light scattering in HPDLCs. A Monte Carlo model has been utilized to model the reflection, transmission, and scattering of light through an HPDLC. The reflections and transmission are modeled using a newly developed method for calculating reflection probabilities for structures in which the interference properties of light effect the light propagation. The scattering is modeled using a discrete dipole approximation approach. Scattering in HPDLCs is experimentally investigated and the results are compared to the Monte Carlo method. The experimental and theoretical results are analyzed to determine microscopic properties of the HPDLC. Finally, contributions to the understanding of light scattering in HPDLCs and other complex scattering media are discussed.
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Details
- Title
- Light scattering in holographic polymer dispersed liquid crystals
- Creators
- Ben E. Pelleg - DU
- Contributors
- Adam Fontecchio (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Engineering (1970-2026); Electrical (and Computer) Engineering (1970-2026); Drexel University
- Other Identifier
- 4564; 991014632153404721