A Transformative Metasurface Based on Zerogap Embedded Template

Abstract

The ideals of reconfigurable metasurfaces would be operation in a broad frequency range with a high extinction ratio and fatigue resistivity. In this paper, all the above is achieved in the microwave regime by transforming a bare metallic film into well-controlled nanometer sized gaps in a fully reversible manner. It is shown that adjacent metallic patterns deposited at different times can form "zero-nanometer gaps," or "zerogaps," while maintaining the optical and electrical connectivity. The zerogaps readily open and recover with gentle bending and relaxing of the flexible substrate, precisely along the rims of the pre-patterns of centimeter lengths. In a prototypical pattern of densely packed slit arrays, these gaps when opened serve as antennas achieving transparency for polarizations perpendicular to the length of the gap and shut off all the incident lights when closed. In such transformation between a polarizer and a mirror, 75% of transmission is observed with polarization extinction ratio of 7500 coming back down to 5 orders of magnitude extinction repeatable over 10 000 times. This work has long-standing implications to metamaterials and metasurfaces as well as the fundamental aspect of extending a picometer scale distance controllability toward the wafer scale.