Alignment‐Free Three‐Dimensional Optical Metamaterials

Abstract

Three-dimensional optical metamaterials based on multilayers typically rely on critical vertical alignment to achieve the desired functionality. Here the conditions under which three-dimensional metamaterials with different functionalities may be realized without constraints on alignment are analyzed and demonstrated experimentally. This study demonstrates that the release of alignment constraints for multilayered metamaterials is allowed, while their anomalous interaction with light is preserved.

A Bilayer Plasmonic Metasurface for Polarization‐Insensitive Bidirectional Perfect Absorption

“…[29,33] The influence of alignment between the bilayer gold nano disks in the proposed metasurface on the bidirectional perfect absorption is validated by designing several bilayer metasurfaces with different degrees of misalignment between the bilayer nano disks. [34] As shown in Figure 3a, three situations involving misalignment along x-axis ( x ), y-axis ( y ), and both xand y-axis ( xy ) are investigated. The simulated results of the absorption spectra of bilayer metasurfaces with different misalignment between the bilayer nano disks under forward x-polarized normal illumination are shown in Figure 3b-d.…”

“…The requirement of precise alignment between the layers in previous few‐layer metasurfaces makes enormous challenges in sample fabrication and cost, which prevent their further application and commercialization . The influence of alignment between the bilayer gold nano disks in the proposed metasurface on the bidirectional perfect absorption is validated by designing several bilayer metasurfaces with different degrees of misalignment between the bilayer nano disks . As shown in Figure 3a, three situations involving misalignment along x ‐axis ( δ x ), y ‐axis ( δ y ), and both x ‐ and y ‐axis ( δ xy ) are investigated.…”

Responsive and Adaptive Micro Wrinkles on Organic‐Inorganic Hybrid Materials

“…The templating effect of wrinkle topography can dominate the share driven alignment while spraying deposition. Most of these type of fabrication requires sophisticated top‐down methods such as laser writing and e‐beam lithography ,. Another unique surface morphology by wrinkling is the hierarchical structures in which wrinkles of different periodicities are fabricated simultaneously.…”

Self-Rolled Multilayer Metasurfaces

“…Nevertheless, despite the off-axis misalignment in the right-handed structure, the signs of the curves are not affected by this. 43 The latter is understandable given that a stack with 30° relative angles does not change its handedness as a function of the relative in-plane positions, as would be the case for NRs with 90° relative angles or other 3D oligomer designs. 42 We also note that the uniform color observed through optical microscopy imaging (see the Supporting Information) suggests we can expect a low variation of the optical response as a function of the measurement position within the overlapping region, due to the periodicity of our structures.…”

“…Although this can be critical for devices relying on 3D structures that are sensitive to the precise layer-to-layer alignment, as in the case of some plasmonic oligomers, 42 other systems, such as twisted NR arrays are more tolerant to some misalignment between layers. 43 In such periodic metasurfaces, pattern-to-pattern misalignments can be reduced by designing arrays with smaller separations between the nano-features. For applications relying on precise vertical alignment between individual elements, we expect that by carefully engineering the self-rolling protocols and implementing methods such as magnetic-field assisted rolling 44 or the recently proposed capillary induced self-aligning process, 45 will improve the precision of stacking-by-rolling.…”