Using nanoscale and mesoscale anisotropy to engineer the optical response of three-dimensional plasmonic metamaterials

Abstract

The a priori ability to design electromagnetic wave propagation is crucial for the development of novel metamaterials. Incorporating plasmonic building blocks is of particular interest due to their ability to confine visible light. Here we explore the use of anisotropy in nanoscale and mesoscale plasmonic array architectures to produce noble metal-based metamaterials with unusual optical properties. We find that the combination of nanoscale and mesoscale anisotropy leads to rich opportunities for metamaterials throughout the visible and nearinfrared. The low volume fraction (o5%) plasmonic metamaterials explored herein exhibit birefringence, a skin depth approaching that of pure metals for selected wavelengths, and directionally confined waves similar to those found in optical fibres. These data provide design principles with which the electromagnetic behaviour of plasmonic metamaterials can be tailored using high aspect ratio nanostructures that are accessible via a variety of synthesis and assembly methods.

Defect tolerance and the effect of structural inhomogeneity in plasmonic DNA-nanoparticle superlattices

“…This suggests that the interparticle plasmonic interactions here are primarily coherent and in-phase; small displacements (relative to their radii) in nanoparticle position do not meaningfully change the weak plasmonic coupling between particles. In turn, many of the emergent plasmonic and photonic effects that we have identified in similar systems (29,34,39) are likely robust to the presence of defects and forgiving to minor variations to the crystalline environment.…”

“…Here, we compare experimental extinction measurements with two types of simulations: (i) Maxwell-Garnett effective medium theory (EMT) and (ii) discrete nanoparticle electrodynamics simulations (ED). In EMT (28,29), the superlattice is described as a sum of its constituent building blocks (e.g., 10% Au particles, 90% water). This effective material is then input into the Fresnel equations to determine the transmission, reflection, and absorption of an infinite thin film (Fig.…”

“…We have previously implemented volume-fraction-based methods with predictable and consistent agreement between experiment and simulation in the far field (28,29,32,34,39). Many of the unique and exciting plasmonic materials that we have explored using programmable DNA assembly depend solely on dipolar interparticle interactions (at low volume fraction) and are fairly insensitive and defect-tolerant.…”

Optical properties of anisotropic 3D nanoparticles arrays

“…Self-assembly of 3D systems of noble metal nanoparticles can be achieved using DNA linkers as a scaffolding [1][2][3]. By changing the number of DNA-base pairs, superlattice engineering of different crystalline structures [4] is possible as well as directional crystallization [5,6]. The many applications derived from DNA superlattice engineering include the assembly of superstructures for biological delivery [7], biosensors [8], tuning of the plasmonic response of superlattices [9,10], ordering of Au nanoparticles in one-dimensional arrays [11,12], among others.…”

“…DNA self-assembled superlattices have become a way to design novel metamaterials with a very specific response to electromagnetic fields [6,9,10]. In this paper, we focus on the use of DNA, which has the advantage that the resulting structures are robust to small variations or perturbations [15] and the inter-particle separation can be finely tuned [16].…”