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Lookup NU author(s): Dr Victor Pacheco PenaORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
In this paper, we design and numerically demonstrate an ultra-thin super-oscillatory metalens with a resolution below the diffraction limit. The zones of the lens are implemented using metasurface concepts with hexagonal unit cells. This way, the transparency and, hence, efficiency is optimized, compared to the conventional transparent–opaque zoning approach that introduces, inevitably, a high reflection in the opaque regions. Furthermore, a novel two-step optimization technique, based on evolutionary algorithms, is developed to reduce the side lobes and boost the intensity at the focus. After the design process, we demonstrate that the metalens is able to generate a focal spot of 0.46λ0 (1.4 times below the resolution limit) at the design focal length of 10λ0 with reduced side lobes (the side lobe level being approximately −11 dB). The metalens is optimized at 0.327 THz, and has been validated with numerical simulations.
Author(s): Legaria S, Pacheo-Pena V, Beruete M
Publication type: Article
Publication status: Published
Online publication date: 05/12/2018
Acceptance date: 29/11/2018
Date deposited: 05/12/2018
ISSN (electronic): 2304-6732
Publisher: MDPI AG
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