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Ordered 3D Thin‐Shell Nanolattice Materials with Near‐Unity Refractive Indices
Author(s) -
Zhang Xu A.,
Bagal Abhijeet,
Dandley Erinn C.,
Zhao Junjie,
Oldham Christopher J.,
Wu BaeIan,
Parsons Gregory N.,
Chang ChihHao
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502854
Subject(s) - materials science , refractive index , dielectric , photonics , atomic layer deposition , optoelectronics , scattering , shell (structure) , stiffness , thin film , resonator , optics , layer (electronics) , composite material , nanotechnology , physics
The refractive indices of naturally occurring materials are limited, and there exists an index gap between indices of air and available solid materials. With many photonics and electronics applications, there has been considerable effort in creating artificial materials with optical and dielectric properties similar to air while simultaneously being mechanically stable to bear load. Here, a class of ordered nanolattice materials consisting of periodic thin‐shell structures with near‐unity refractive index and high stiffness is demonstrated. Using a combination of 3D nanolithography and atomic layer deposition, these ordered nanostructured materials have reduced optical scattering and improved mechanical stability compared to existing randomly porous materials. Using ZnO and Al 2 O 3 as the building materials, refractive indices from 1.3 down to 1.025 are achieved. The experimental data can be accurately described by Maxwell Garnett effective media theory, which can provide a guide for index design. The demonstrated low‐index, low‐scattering, and high‐stiffness materials can serve as high‐quality optical films in multilayer photonic structures, waveguides, resonators, and ultra‐low‐ k dielectrics.