Merging Top‐Down and Bottom‐Up Approaches to Fabricate Artificial Photonic Nanomaterials with a Deterministic Electric and Magnetic Response

Abstract

Artificial photonic nanomaterials made from densely packed scatterers are frequently realized either by top‐down or bottom‐up techniques. While top‐down techniques offer unprecedented control over achievable geometries for the scatterers, by trend they suffer from being limited to planar and periodic structures. In contrast, materials fabricated with bottom‐up techniques do not suffer from such disadvantages but, unfortunately, they offer only little control on achievable geometries for the scatterers. To overcome these limitations, a nanofabrication strategy is introduced that merges both approaches. A large number of scatterers are fabricated with a tailored optical response by fast character projection electron‐beam lithography and are embedded into a membrane. By peeling‐off this membrane from the substrate, scrambling, and densifying it, a bulk material comprising densely packed and randomly arranged scatterers is obtained. The fabrication of an isotropic material from these scatterers with a strong electric and magnetic response is demonstrated. The approach of this study unlocks novel opportunities to fabricate nanomaterials with a complex optical response in the bulk but also on top of arbitrarily shaped surfaces.

The Beginner's Guide to Chiral Plasmonics: Mostly Harmless Theory and the Design of Large‐Area Substrates

“…[226] The resulting random orientation of the plasmonic nanostructures affords densely packed films with isotropic optical responses. [227] 3D Chiral Oligomers: Defined arrangements of several individual nanoparticles are often termed plasmonic oligomers. [75,86,87] The plasmonic resonances of the individual nanoparticles are coupled to produce collective modes of the entire oligomer.…”

“…[ 226 ] The resulting random orientation of the plasmonic nanostructures affords densely packed films with isotropic optical responses. [ 227 ]…”

Self-Assembled Arrays of Gold Nanorod-Decorated Dielectric Microspheres with a Magnetic Dipole Response in the Visible Range for Perfect Lensing and Cloaking Applications

“…This led to the notion of metasurfaces rather than metamaterials. Combining top-down and bottom-up might solve the problem of the anisotropy, but still, the desire to have bulk materials at hand strongly favors bottom-up self-assembly methods …”

“…Combining topdown and bottom-up might solve the problem of the anisotropy, but still, the desire to have bulk materials at hand strongly favors bottom-up self-assembly methods. 21 However, the existing approach where metallic nanospheres decorate the core dielectric sphere has some limitations. In particular, because the resonance wavelength of the nanosphere is basically fixed once the material from which it is made has been chosen, there is nearly no degree of freedom left to tune the resonance wavelength of the induced magnetic dipole moment.…”