Share Email Print

Proceedings Paper

Metastructures consisting of cascaded high-contrast subwavelength gratings
Author(s): Steve Young; Luke Szymanski; Anthony Grbic
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Transmissive and reflective all-dielectric metastructures will be presented that offer tailored polarization con- versions and spectral responses. The metastructures consist of stacked deeply subwavelength, high contrast gratings of different fill factors and rotations. Broadband metastructures that perform a given polarization conversion over a wide continuous bandwidth will be shown, as well as multiband metastructures that perform a common polarization conversion over different bands. Multifunctional metastructures that realize different polarization conversions over different bands will also be reported at the conference. Unlike earlier stacked grating geometries, the transmissive metastructures do not require antireflection layers since impedance matching is incorporated into their design. The subwavelength gratings are modeled as homogeneous anisotropic layers, allowing an overall metastructure to be treated as a stratified dielectric medium. Quasi-static analysis is used to homogenize the subwavelength gratings and represent them with effective dielectric constants. Plane-wave transfer matrix techniques are employed to model the interactions between gratings, allowing for rapid design and optimization. In the metastructures, higher-order Floquet harmonics are bound to the gratings due to their subwavelength periodicities. As a result, only zeroth-order coupling between the gratings needs to be considered. The multifunctional performance and compactness (wavelength-sized thickness) of the proposed devices will find use at millimeter-wave wavelengths and beyond. Two example designs are described in this paper. Measured performance of prototypes will also be reported at the conference and various fabrication approaches reviewed. This work demonstrates the flexibility with which cascaded subwavelength gratings can realize unprecedented polarization control with varied spectral responses.

Paper Details

Date Published: 26 February 2020
PDF: 8 pages
Proc. SPIE 11290, High Contrast Metastructures IX, 112900Z (26 February 2020); doi: 10.1117/12.2543368
Show Author Affiliations
Steve Young, Univ. of Michigan (United States)
Luke Szymanski, Univ. of Michigan (United States)
Anthony Grbic, Univ. of Michigan (United States)

Published in SPIE Proceedings Vol. 11290:
High Contrast Metastructures IX
Connie J. Chang-Hasnain; Andrei Faraon; Weimin Zhou, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?