Realizing electromagnetic metamaterials which operate in the optical regime requires creating precise arrangements of sub-100 nm building blocks. As such, fabricating these materials using conventional lithographic methods is extremely costly. On the other hand, bottom-up assembly of nanoparticles into crystalline superlattices offers opportunities to explore the scalable fabrication of 2- (2D) and 3-dimensional (3D) metamaterials. Of various nanoparticle assembly methods, colloidal crystal engineering with DNA is unique in that the specificity of DNA binding allows one to deliberately prepare materials with predesigned structures. This thesis takes a materials-by-design approach towards using DNA to assemble nanoparticles into optical metamaterials with targeted properties. Throughout the thesis, metamaterials on multiple dimensionalities are explored. Chapter 2 describes the template-mediated assembly of individual nanocube-on-mirror anntenas into 2D photonic lattices, and the interaction of these antennas with precisely embedded emitter molecules. Chapter 3 explores using DNA to assemble high volume fraction, 3D metacrystals which give rise to tunable, mid-IR Mie resonances. In Chapters 4 and 5, methods to assemble 2D metasurfaces from anisotropic nanoparticles on the wafer-scale are discussed. Furthermore, the metasurfaces are designed to exhibit actively tunable near-IR resonances and epsilon-near-zero (ENZ) conditions. Expanding on the results in Chapter 3, Chapter 6 reports the preparation of uniform arrays of 3D metacrystals, by confining superlattice growth inside microscale trenches. First, the growth mechanism and outcomes are probed using a combination of electron microscopy and synchrotron X-ray based techniques. Next, the efficacy of the method towards large-scale fabrication of uniform 3D metacrystals is explored. Finally, an additional degree of hierarchy is introduced by arranging 3D metacrystals into periodic lattices, which give rise to diffractive modes. Taken together, these discoveries significantly advance the scalable assembly of 2D and 3D optical metamaterials, which could find use in numerous applications including sensing, telecommunications, and optical computing.

Creator

• Zheng, Cindy Yizhe

DOI

• https://doi.org/10.21985/n2-ndf2-tj60

Subject

• Chemistry

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15883
• etdadmin_upload_864457

Date created

• 2021-01-01

Resource type

• Dissertation

Rights statement

• In Copyright