title: Plasmonic Lattice Lenses for Multiwavelength Achromatic Focusing.
abstract: This paper describes an evolutionary approach to design flat multiwavelength achromatic lenses based on subwavelength plasmonic nanoparticles. Our lattice evolution algorithm achieved desired optical responses by tuning the arrangement of the phase units on a discrete square lattice. Lattice lenses consisting of a single type of nanoparticle could operate at any wavelength in the visible to near-infrared regime (540-1000 nm) by tailoring the localized surface plasmon resonance. When the unit cells were expanded to anisotropic particle shapes, the planar optics could selectively focus light depending on the polarization of incident light. Finally, the algorithm realized efficient multiobjective optimization and produced achromatic lattice lenses at up to three wavelengths (λ = 600 nm, λ = 785 nm, and λ = 980 nm) using multiple different nanoparticle shapes.
authors: Department of Materials Science and Engineering and ‡Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors: Jingtian
authors: J
authors: Hu
authors: Department of Materials Science and Engineering and ‡Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors: Chang-Hua
authors: CH
authors: Liu
authors: Department of Materials Science and Engineering and ‡Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors: Xiaochen
authors: X
authors: Ren
authors: Department of Materials Science and Engineering and ‡Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors: Lincoln J
authors: LJ
authors: Lauhon
authors: Department of Materials Science and Engineering and ‡Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors: Teri W
authors: TW
authors: Odom
keywords: achromatic focusing; evolutionary algorithm; flat lenses; gold nanoparticles; metasurface; predictive design