Bulk optical metamaterials assembled by microfluidic evaporation

We present high refractive index optical metamaterials assembled via a microfluidic evaporation technique. This technique enables fabrication of truly three-dimensional bulk samples from a suspension of nanoparticles with a number of layers well in excess of 600, surpassing rival techniques by at least an order of magnitude. In addition to their large dimensions, the assembled metamaterials show a high degree of homogeneity and warrant an easy and rapid optical characterization using spectroscopic ellipsometry. We believe that the suggested inexpensive method considerably reduces the complexity in assembling optical metamaterials and opens new avenues in engineering bulk optical devices by choice of nanoparticle composition and geometry.