THz meta-foil - a platform for practical applications of metamaterials

The meta-foil, an all-metal fully self-supported locally stiff and globally flexible metamaterial, is presented. Its architecture is based on an array of parallel S-strings interconnected by transverse metal rods that are periodically repeated along the strings. For the present samples, this period is about once or twice the length of an S, which is 31 mu m. The resonance frequency of the left-handed pass-band is 3.2 THz or somewhat higher depending on geometry. The meta-foil is manufactured by UV or X-ray lithography-based microfabrication. In the end, it may be produced cost-effectively by plastic moulding. The physical function is explained by numerical simulation and equivalent circuit theory. The spectra are measured by Fourier transform infrared spectroscopy. Maximum transmission is achieved at normal incidence with a cosine-square-like decrease with incidence angle. A change of geometrical parameters alters the resonance frequency as expected. The spectra are also rather sensitive to surrounding dielectrics, indicating a sensor capability. As the meta-foil can be bent, a cylindrical hyperlens set-up is discussed as a forthcoming application to sub-wavelength resolution imaging.