Realization of metamaterial structures by non-lithographic processes

The opportunities presented by the use of metamaterials have been the subject of extensive discussions. However, a large fraction of the work available to date has been limited to simulations and proof-of-principle demonstrations. One reason for the limited success inserting these structures into functioning systems and real-world applications is the high level of complexity involved in their fabrication. Most approaches to the realization of metamaterial structures utilize traditional lithographic processing techniques to pattern the required geometries and then rely on separate steps to assemble the final design. Obviously, composite structures with arbitrary and/or 3-D geometries present a challenge for their implementation with these approaches. Non-lithographic processes are ideally suited for the fabrication of arbitrary periodic and aperiodic structures needed to implement many of the metamaterial designs being proposed. Furthermore, non-lithographic techniques are true enablers for the development of conformal or 3-D metamaterial designs. This article will show examples of metamaterial structures developed at the Naval Research Laboratory using non-lithographic processes. These processes have been applied successfully to the fabrication of complex 2-D and 3-D structures comprising different types of materials.