Metamaterials 2010

Besides its basic scientific interest, work on electromagnetic metamaterials is spurred by a plethora of promising applications. The development of metamaterials for a spectral range from a fraction of THz to several hundred of THz is benefiting twice from synchrotron radiation, once through micro/nanomanufacturing involving X-ray deep lithography and again through the spectral characterisation by means of (synchrotron) infrared radiation. Unique among metamaterials, the meta-foil is an all-metal self-supported space grid that is locally stiff and globally flexible down to bending radii of about 100 µm for the current implementations. The architecture of the meta-foil is based on the well-known S-strings with the new element of the interconnecting lines that are arranged transversely to the S-strings to hold them together. As the interconnecting lines are placed in the nodes of the oscillations along the S string, they are basically electrically neutral and do not quench resonances. On the other hand, they create new resonance loops that can be seen in the spectrum. In current nSX architectures n stands for the distance of interconnecting lines in multiples of the length (a–h), currently n=1 or n=2, and X for E-equidistant, or P-paired, meaning that in the E-case all S-strings are separated by the gap width d while in the P-case S-strings are paired with a gap of d, but pairs have a larger distance among themselves – in the present case, 2d. Up to now, S-strings and interconnecting lines form right angles, but other architectures have also been envisioned. The mechanical strength and the spectral location of the resonances can be influenced by the periodicity and the geometry of the interconnecting lines. The spectral response of the meta-foil has been characterized by means of infrared Fourier transform spectroscopy in the terahertz region.