Design and realization of functional metamaterial basis structures through optical phase manipulation based interference lithography

Functional metamaterials are of interest to research due to their exotic response to electromagnetic field, leading to interesting properties and wide applications that are unachievable in nature. Most of the study in this field is limited to theory and currently there are certain multi-step experimental studies reported. However, there is not much exploration of an interference lithography technique that is rapid and cost effective to realize such structures over a large area and in bulk (3D) for real world applications. We present the design of 2D and 3D periodic functional metamaterial basis structures arranged in a square and hexagonal lattice using the interference of multiple phase manipulated plane beams. The designed structures are realized in a single step using a phase only spatial light modulator (SLM) assisted Fourier filtering experimental setup in a few seconds. The phase and amplitude of the individual interfering beams are manipulated computationally using MATLAB to generate an irradiance profile for metamaterial structures of different basis features and orientations. The designed structures are: a linearly packed rectangular array, a hexagonally packed rectangular array, ta riangular lattice array, a star, U, V, C, dual-symmetric and dual-asymmetric shaped structures. Three dimensional stacks of such structures can also be realized involving an axial beam into the plane of interference. Templates of some of the microstructures are realized on a positive photoresist that have a spatial periodicity of 6.5 mu m. The transfer of the realized patterns to a suitable metallodielectric medium may find interesting applications reported so far in the literature or may lead to some interesting applications.