@article{6e047e19211d456e98f7246e4a5b86d7,
title = "Evolutionary Design and Prototyping of Single Crystalline Titanium Nitride Lattice Optics",
abstract = "This paper describes the design and prototyping of single-crystalline TiN plasmonic metasurfaces based on subwavelength hole arrays. An evolutionary algorithm with a multiobjective fitness function was developed to produce a variety of three-dimensional (3D) light profiles with balanced intensities at the light spots. We also demonstrated a simple, efficient technique to prototype these lattice designs in large-area TiN films by combining focused ion beam milling and wet chemical etching. Multilevel phase control was achieved by tuning nanohole size, and multipoint focusing with arbitrary light spot patterns was realized. Using anisotropic nanohole shapes, the TiN lattice lenses could exhibit dynamic tuning of the focal profiles by changing the polarization of incident light.",
keywords = "evolutionary algorithm, flat optics, metasurface, surface plasmon, titanium nitride",
author = "Jingtian Hu and Xiaochen Ren and Reed, {Amber N.} and Thaddeus Reese and Dongjoon Rhee and Brandon Howe and Lauhon, {Lincoln J.} and Urbas, {Augustine M.} and Odom, {Teri W.}",
note = "Funding Information: This material is based on research sponsored by the Air Force Research laboratory under agreement number FA8650-15-2- 5518. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the U.S. Government. This work was also supported by the Air Force Office of Scientific Research (AFOSR) under grant FA9550-14-1-0274 (J.H., T.W.O.). We are grateful for the use of EPIC, Keck-II, and/or SPID facility(ies) of Northwestern University?s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205), the MRSEC program (NSF DMR- 1121262) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois, through the IIN. This research was also supported in part by computational resources and staff contributions provided for the Quest high performance computing facility at Northwestern University which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology. Publisher Copyright: {\textcopyright} 2017 American Chemical Society. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.",
year = "2017",
month = mar,
day = "15",
doi = "10.1021/acsphotonics.6b00955",
language = "English",
volume = "4",
pages = "606--612",
journal = "ACS Photonics",
issn = "2330-4022",
publisher = "American Chemical Society",
number = "3",
}