Experimental demonstration of ultrathin broken-symmetry metasurfaces with controllably sharp resonant response

TL;DR

This paper experimentally demonstrates ultrathin broken-symmetry metasurfaces at millimeter wave frequencies, achieving sharp spectral resonances with high quality factors, on flexible, low-loss substrates, enabling diverse applications like filtering and sensing.

Contribution

It introduces a novel fabrication of ultrathin, flexible broken-symmetry metasurfaces with experimentally verified high-Q resonances in the millimeter wave spectrum.

Findings

Achieved quality factors of several hundreds.

Verified sharp spectral features experimentally.

Demonstrated polarization-dependent responses consistent with Babinet's principle.

Abstract

Symmetry-protected resonances can be made to couple with free space by introducing a small degree of geometric asymmetry, leading to controllably-sharp spectral response. Here, we experimentally demonstrate a broken-symmetry metasurface for the technologically important low millimeter wave spectrum. The proposed metasurface is fabricated on an ultrathin polyimide substrate, resulting in a low loss and flexible structure. Measurements inside an anechoic chamber experimentally verify the theoretically predicted sharp spectral features corresponding to quality factors of several hundreds. The demonstrated sharp response is also observed with the complementary structure which responds to the orthogonal linear polarization (Babinet's principle). The designed metasurfaces can be exploited in diverse applications favoured by a controllably-sharp spectral response, e.g., filtering, sensing, switching, nonlinear applications, in either reflection or transmission mode operation. More generally, the demonstrated fabrication process provides a generic platform for low-cost, large-scale engineering of metasurfaces with minimal substrate-induced effects.