Synthesis, characterization, and experimental investigation of photonic crystals derived from biology

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Title Synthesis, characterization, and experimental investigation of photonic crystals derived from biology
Publication Type dissertation
School or College College of Science
Department Chemistry
Author Jorgensen, Matthew Ray
Date 2012-05
Description The synthesis, characterization, and nonclassical optical properties of photonic crystals (PCs) created from naturally occurring biological templates was studied. Biotemplated PCs were created from several different natural structures using sol-gel chemistry methods. PCs were characterized using a combination of reflection spectroscopy, SEM image analysis, three-dimensional structure modeling, photonic band structure calculations, and density of optical states calculations. The effect our PCs had on the density of optical states (DOS) was probed using time correlated single photon counting spectroscopy. By carefully controlling the sol-gel chemistry used in the templating process, it is possible to synthesize hollow silica inverse, solid silica inverse, hollow titania inverse, solid titania inverse, and solid titania replicate structures. The inverse-type structures have the advantage of being accessible through a single templating step, while the titania replica is capable of a predicted full photonic band gap. Each structure was investigated using methods mentioned above. The reliability of reflectance spectroscopy was investigated. It was found that in certain cases, a continuum of structural parameters yield reflections that match photonic band structure calculations. Methods to improve this situation are discussed. When applied to titania inverse opals, it was found that the refractive index could be determined to ±0.05 and the volume fraction to ±0.5%. Accurately determining the refractive index of inverse opals is useful in estimating the refractive index of other PCs made from the same sol-gel. Calculation of the DOS using a combination of MIT's photonic bands package and house-written software was applied to biotemplated photonic crystals. It was found that even partial band gap photonic crystals can greatly modify the DOS. Finally, the rate of spontaneous emission of quantum dots embedded in photonic crystals was measured to indirectly probe the DOS. Three different models were used to extract the lifetime from radiative decay curves. It was found that a log-normal distribution of lifetimes was the most meaningful model. The radiative lifetime of quantum dots embedded in titania photonic crystals replicated from Lamprocyphus augustus was modified by up to a factor of ten, an amount unprecedented in the photonic crystal literature.
Type Text
Publisher University of Utah
Subject Biomimetic; Density of optical states; Photonic crystals; Radiative lifetime
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © Matthew Ray Jorgensen 2012
Format application/pdf
Format Medium application/pdf
Format Extent 6,670,041 bytes
Identifier us-etd3,87327
ARK ark:/87278/s6n30brf
Setname ir_etd
ID 195676
Reference URL https://collections.lib.utah.edu/ark:/87278/s6n30brf
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