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Title: Wave propagation in photonic crystals and metamaterials: Surface waves, nonlinearity and chirality

Wave propagation in photonic crystals and metamaterials: Surface waves, nonlinearity and chirality Photonic crystals and metamaterials, both composed of artificial structures, are two interesting areas in electromagnetism and optics. New phenomena in photonic crystals and metamaterials are being discovered, including some not found in natural materials. This thesis presents my research work in the two areas. Photonic crystals are periodically arranged artificial structures, mostly made from dielectric materials, with period on the same order of the wavelength of the working electromagnetic wave. The wave propagation in photonic crystals is determined by the Bragg scattering of the periodic structure. Photonic band-gaps can be present for a properly designed photonic crystal. Electromagnetic waves with frequency within the range of the band-gap are suppressed from propagating in the photonic crystal. With surface defects, a photonic crystal could support surface modes that are localized on the surface of the crystal, with mode frequencies within the band-gap. With line defects, a photonic crystal could allow the propagation of electromagnetic waves along the channels. The study of surface modes and waveguiding properties of a 2D photonic crystal will be presented in Chapter 1. Metamaterials are generally composed of artificial structures with sizes one order smaller than the wavelength and can be approximated as effective media. Effective macroscopic parameters more » such as electric permittivity {epsilon}, magnetic permeability {mu} are used to characterize the wave propagation in metamaterials. The fundamental structures of the metamaterials affect strongly their macroscopic properties. By designing the fundamental structures of the metamaterials, the effective parameters can be tuned and different electromagnetic properties can be achieved. One important aspect of metamaterial research is to get artificial magnetism. Metallic split-ring resonators (SRRs) and variants are widely used to build magnetic metamaterials with effective {mu} < 1 or even {mu} < 0. Varactor based nonlinear SRRs are built and modeled to study the nonlinearity in magnetic metamaterials and the results will be presented in Chapter 3. Negative refractive index n is one of the major target in the research of metamaterials. Negative n can be obtained with a metamaterial with both {epsilon} and {mu} negative. As an alternative, negative index for one of the circularly polarized waves could be achieved with metamaterials having a strong chirality ?. In this case neither {epsilon} nor {mu} negative is required. My work on chiral metamaterials will be presented in Chapter 4. « less
Authors:
Publication Date:
OSTI Identifier:972072
Report Number(s):IS-T 2645
TRN: US201005%%174
DOE Contract Number:DE-AC02-07CH11358
Resource Type:Thesis/Dissertation
Data Type:
Research Org:Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:USDOE Office of Science (SC)
Country of Publication:United States
Language:English
Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHIRALITY; DEFECTS; DIELECTRIC MATERIALS; ELECTROMAGNETIC RADIATION; ELECTROMAGNETISM; LINE DEFECTS; MAGNETIC SUSCEPTIBILITY; MAGNETISM; OPTICS; PERMITTIVITY; REFRACTIVE INDEX; RESONATORS; SCATTERING; TARGETS; VARIABLE CAPACITANCE DIODES; WAVE PROPAGATION; WAVELENGTHS