Nanoimprinting techniques for large-area three-dimensional negative index metamaterials with operation in the visible and telecom bands

We report advances in materials, designs, and fabrication schemes for large-area negative index metamaterials (NIMs) in multilayer fishnet layouts that offer negative index behavior at wavelengths into the visible regime. A simple nanoimprinting scheme capable of implementation using standard, widely available tools followed by a subtractive, physical liftoff step provides an enabling route for the fabrication. Computational analysis of reflection and transmission measurements suggests that the resulting structures offer negative index of refraction that spans both the visible wavelength range (529-720 nm) and the telecommunication band (1.35-1.6 μm). The data reveal that these large (>75 cm²) imprinted NIMs have predictable behaviors, good spatial uniformity in properties, and figures of merit as high as 4.3 in the visible range.