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Array-Level Inverse Design of Beam Steering Active Metasurfaces

Thureja, Prachi and Shirmanesh, Ghazaleh Kafaie and Fountaine, Katherine T. and Sokhoyan, Ruzan and Grajower, Meir and Atwater, Harry A. (2020) Array-Level Inverse Design of Beam Steering Active Metasurfaces. ACS Nano, 14 (11). pp. 15042-15055. ISSN 1936-0851. https://resolver.caltech.edu/CaltechAUTHORS:20201102-102851756

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Abstract

We report an array-level inverse design approach to optimize the beam steering performance of active metasurfaces, thus overcoming the limitations posed by nonideal metasurface phase and amplitude tuning. In contrast to device-level topology optimization of passive metasurfaces, the outlined system-level optimization framework relies on the electrical tunability of geometrically identical nanoantennas, enabling the design of active antenna arrays with variable spatial phase and amplitude profiles. Based on this method, we demonstrate high-directivity, continuous beam steering up to 70° for phased arrays with realistic tunable antenna designs, despite nonidealities such as strong covariation of scattered light amplitude with phase. Nonintuitive array phase and amplitude profiles further facilitate beam steering with a phase modulation range as low as 180°. Furthermore, we use the device geometries presented in this work for experimental validation of the system-level inverse design approach of active beam steering metasurfaces. The proposed method offers a framework to optimize nanophotonic structures at the array level that is potentially applicable to a wide variety of objective functions and actively tunable metasurface antenna array platforms.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acsnano.0c05026DOIArticle
ORCID:
AuthorORCID
Thureja, Prachi0000-0003-3852-3395
Shirmanesh, Ghazaleh Kafaie0000-0003-1666-3215
Fountaine, Katherine T.0000-0002-0414-8227
Sokhoyan, Ruzan0000-0003-4599-6350
Grajower, Meir0000-0003-0726-8811
Atwater, Harry A.0000-0001-9435-0201
Additional Information:© 2020 American Chemical Society. Received: June 16, 2020; Accepted: October 6, 2020; Published: October 30, 2020. The authors thank L. Sweatlock and P. Hon regarding preliminary discussions about the project and Y. Tokpanov for discussions regarding optimization algorithms. The authors acknowledge metasurface device fabrication support provided by the Kavli Nanoscience Institute (KNI). The FDTD computations presented here were conducted on the Caltech High Performance Cluster, partially supported by a grant from the Gordon and Betty Moore Foundation. Author Contributions. P.T. and G.K.S. contributed equally to this work. Author Contributions: P.T., G.K.S., R.S., and H.A.A. conceived the original idea. P.T. analyzed forward design methods, designed the iterative genetic optimization, performed several optimization studies, analyzed the experimental results, and wrote the manuscript. G.K.S. and R.S. performed the design and simulations of the electro-optically tunable metasurface. G.K.S performed the FDTD simulations and numerical design, fabricated the metasurface device, performed the optical measurements, and extracted the experimental data. K.T.F. helped with the analysis of forward design methods and the design of the genetic algorithm. R.S. and M.G. supported in designing theoretical studies and performing data analysis. G.K.S. and M.G. built the experimental setup. H.A.A. organized the project, designed optimization studies, analyzed the results, and prepared the manuscript. All authors have given approval to the final version of the manuscript. This work was supported by National Aeronautics and Space Administration (NASA) Early Stage Innovation (ESI) Grant 80NSSC19K0213 and Samsung Electronics. The authors declare no competing financial interest.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
Kavli Nanoscience InstituteUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
NASA80NSSC19K0213
Samsung ElectronicsUNSPECIFIED
Subject Keywords:inverse design, active metasurface, phased array, beam steering, array configuration, genetic algorithm, wavefront engineering
Issue or Number:11
Record Number:CaltechAUTHORS:20201102-102851756
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20201102-102851756
Official Citation:Array-Level Inverse Design of Beam Steering Active Metasurfaces. Prachi Thureja, Ghazaleh Kafaie Shirmanesh, Katherine T. Fountaine, Ruzan Sokhoyan, Meir Grajower, and Harry A. Atwater. ACS Nano 2020 14 (11), 15042-15055; DOI: 10.1021/acsnano.0c05026
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106383
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:04 Nov 2020 17:14
Last Modified:25 Nov 2020 17:08

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