Fabrication of Large Area Fishnet Optical Metamaterial Structures Operational at Near-IR Wavelengths

In this paper, we demonstrate a fabrication process for large area (2 mm × 2 mm) fishnet metamaterial structures for near IR wavelengths. This process involves: (a) defining a sacrificial Si template structure onto a quartz wafer using deep-UV lithography and a dry etching process (b) deposition of a stack of Au-SiO₂-Au layers and (c) a 'lift-off' process which removes the sacrificial template structure to yield the fishnet structure. The fabrication steps in this process are compatible with today's CMOS technology making it eminently well suited for batch fabrication. Also, depending on area of the exposure mask available for patterning the template structure, this fabrication process can potentially lead to optical metamaterials spanning across wafer-size areas.