Aperiodic plasmonics : manipulating light with nanostructured groove arrays on metallic surfaces
Abstract/Contents
- Abstract
- In the age of computers, there has been growing interest in many areas of science and engineering to use numerical techniques to explore problems that are mathematically or analytically intractable. In photonics specifically, there is a desire to design and realize non-periodic nanophotonic structures that outperform their periodic counterparts. One major obstacle to this goal is the necessity to solve the computationally expensive Maxwell's equations repeatedly over a vast parameter space. Here, we will apply the technique of numerical optimization to design aperiodic plasmonic nanostructures. Plasmonics, the study of driven collective oscillations of free electrons in metals, provides for optical modes with subwavelength footprints and is a promising compromise between the small world of electronics and the fast world of photonics. It is well known that nanostructured grooves and slits on a metallic surface are very strong generators and scatterers of surface plasmons, yet the geometries involved make exact analytical solutions impossible. The first step toward designing aperiodic plasmonic groove structures is to identify the fundamental building block of such structures, the metal-air groove, and simplify its mathematical representation so that calculations can be performed very quickly. After the building blocks are described in sufficient detail, the next step is the mathematical model that relates the individual building blocks together in a complete structure. We develop a computation strategy based on a transfer matrix model that can be used to calculate the plasmonic scattering properties of a number of closely spaced grooves to acceptable accuracy with extreme speed. Having characterized the building blocks and the model that glues them together, we apply these results, together with an optimization procedure, to design interesting aperiodic plasmonic groove structures. We first demonstrate a unidirectional launcher of surface plasmons from normally incident light with an extinction ratio of 55 to 1 using only five grooves. The unidirectional launcher is a great starting point due to its simplicity -- relatively few grooves are needed and there is only one operational wavelength, and yet the parameter space is already large enough to necessitate numerical optimization. Building on top of these results, we will conclude with an investigation of structures that split light into specific regions depending on their wavelength. This thesis demonstrates the ability to control the scattering and localization of plasmons using very few carefully chosen scattering elements, and the work presented here can be harnessed to design the next generation of subwavelength photonic devices.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Huang, Xinpeng |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Brongersma, Mark L |
| Thesis advisor | Brongersma, Mark L |
| Thesis advisor | Fan, Shanhui, 1972- |
| Thesis advisor | Vuckovic, Jelena |
| Advisor | Fan, Shanhui, 1972- |
| Advisor | Vuckovic, Jelena |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Xinpeng Huang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Xinpeng Huang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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