Self-supported all-metal THz metamaterials

Abstract

Ideal metamaterials would consist of metal conductors only that are necessary for negative ε and μ. However, most of present-day metamaterials include dielectrics for various support functions. Overcoming dielectrics, we manufactured free-standing THz metamaterials as bi-layer chips of S-string arrays suspended by window-frames at a small gap that controls the resonance frequency. Remaining problems concerning their useful range of incidence angles and the possibility of stacking have been solved by manufacturing the first self-supported free-standing all-metal metamaterials featuring upright S-strings interconnected by metal rods. Large-area slabs show maximum magnetic coupling at normal incidence with left-handed resonances between 3.2 - 4.0 THz. Such metamaterials which we dub the meta-foil represent an ideal platform for including index-gradient optics to achieve optical functionalities like beam deflection and imaging. © 2009 SPIE.