Nanomanufacturing of functional nanostructured surfaces for efficient light transport

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.

Bibliographic Details
Main Author: Kim, Jeong-Gil
Other Authors: George Barbastathis.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2015
Subjects:
Online Access:http://hdl.handle.net/1721.1/100128
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author Kim, Jeong-Gil
author2 George Barbastathis.
author_facet George Barbastathis.
Kim, Jeong-Gil
author_sort Kim, Jeong-Gil
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description Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
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spelling mit-1721.1/1001282019-04-09T16:20:29Z Nanomanufacturing of functional nanostructured surfaces for efficient light transport Kim, Jeong-Gil George Barbastathis. Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering. Mechanical Engineering. Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015. Cataloged from PDF version of thesis. Includes bibliographical references. Nanostructured surfaces have given rise to many unique optical properties, such as broadband anti-reflectivity, structural coloring effects, and enhanced light extraction from high refractive index materials due to their potential to modulate optical behavior on their surfaces. This thesis focuses on design, analysis, and fabrication of functional nanostructured surfaces for efficient light transport, seeking optimized optical performance, high mechanical robustness, and manufacturability, with the aim of increasing the practicality of the photonic nanostructures. First, for the case when light propagates from a low-index material to a high-index material, I designed and fabricated an array of inverted nanocones that realizes anti-reflectivity with robust mechanical strength. The surface exhibits broadband, omnidirectional anti-reflectivity due to the axially varying effective refractive index of the inverted nanocone arrays. The surface also maintains its optical performance after being externally loaded, thanks to low stress concentration and small deflection of the inverted nanocone structure. In addition, for multi-optical interfacial surfaces, double-gradient- index nanostructures are proposed and demonstrated in order to achieve ultimate anti-reflectivity. The top surface, textured with inverted nanocones, maintains high mechanical robustness. Second, for the case where light has to be extracted from high-index materials, a conical photonic crystal is proposed and demonstrated. The tapered conical geometry suppresses Fresnel reflections at the optical interfaces due to adiabatic impedance matching. Periodicity of the arrays of cones diffracts light into higher-order modes with different propagating angles, enabling certain photons to overcome total internal reflection (TIR). After optimizing the structural geometries to balance Fresnel reflection and TIR, light yield efficiency is characterized experimentally on scintillator surfaces. In order to enhance the adaptability to industrial manufacturing, the fabrication methods are based on replicating the photonic nanostructures into a UV-curable polymer, with the help of laser interference lithography as a method of fabricating a master mold. Advanced techniques such as vacuum assisted-filling and a selective delaminating method are also developed to produce nanostructures more effectively. The novel nanostructured surfaces designed in the thesis, and the ability to imprint these topographies through several generations, are promising for large-scale commercial applications where efficient light transport is important. by Jeong-Gil Kim. Ph. D. 2015-12-03T20:55:10Z 2015-12-03T20:55:10Z 2015 2015 Thesis http://hdl.handle.net/1721.1/100128 929668989 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 116 pages application/pdf Massachusetts Institute of Technology
spellingShingle Mechanical Engineering.
Kim, Jeong-Gil
Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title_full Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title_fullStr Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title_full_unstemmed Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title_short Nanomanufacturing of functional nanostructured surfaces for efficient light transport
title_sort nanomanufacturing of functional nanostructured surfaces for efficient light transport
topic Mechanical Engineering.
url http://hdl.handle.net/1721.1/100128
work_keys_str_mv AT kimjeonggil nanomanufacturingoffunctionalnanostructuredsurfacesforefficientlighttransport