Design, Fabrication, and Characterization of 3D Nanolattice Photonic Crystals for Bandgap and Refractive Index Engineering

Citation

Chernow, Victoria Fay (2018) Design, Fabrication, and Characterization of 3D Nanolattice Photonic Crystals for Bandgap and Refractive Index Engineering. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/FK5P-FA29. https://resolver.caltech.edu/CaltechTHESIS:05112018-154344223

Abstract

Three-dimensional (3D) photonic crystals (PhCs) have been the focus of ever-increasing interest in the scientific community given their potential to impact areas spanning energy conversion to analyte sensing. These architected materials are defined by a refractive index that is spatially modulated with a period comparable to that of the electromagnetic wavelength. As a result, constructive and destructive interference due to multiple scattering gives rise to a band structure for photons which may contain gaps. Both bands and bandgaps can be engineered to specifically manipulate light propagation by 3D PhCs. In this work we explore the effect of lattice architecture, finite-size effects, and material constraints on stopband position and emergence of band dispersion phenomena like negative refraction. We show that uniaxial mechanical compression can be used to stably and reversibly tune stopband position in 3D polymer nanolattice PhCs with octahedron unit-cell geometry. We then explore how lattice architecture, namely the differences in 3D cubic space group and finite size effects impact experimentally observable stopbands, and assess the degree to which the stopband behavior of real PhCs can be adequately described by the photonic band structure for an infinite, ideal PhC. Finally, we discuss the design, fabrication, and characterization of a core-shell 3D nanolattice PhC which exhibits an effective negative refractive index in the mid-infrared range.

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