Plasmon Hybridization in Stacked Double Crescents Arrays Fabricated by Colloidal Lithography

Abstract

We apply colloidal lithography to construct stacked nanocrescent dimer structures with an exact vertical alignment and a separation distance of approximately 10 nm. Highly ordered, large arrays of these nanostructures are accessible using nonclose-packed colloidal monolayers as masks. Spatially separated nanocrescent dimers are obtained by application of spatially distributed colloids. The polarization dependent optical properties of the nanostructures are investigated in detail and compared to single crescents. The close proximity of the nanocrescents leads to a coupling process that gives rise to new optical resonances which can be described as linear superpositions of the individual crescents' plasmonic modes. We apply a plasmon hybridization model to explain the spectral differences of all polarization dependent resonances and use geometric arguments to explain the respective shifts of the resonances. Theoretical calculations are performed to support the hybridization model and extend it to higher order resonances not resolved experimentally.

A colloidoscope of colloid-based porous materials and their uses

“…117,120 Figure 4A,iii shows the fabrication of arrays of crescent shaped nanoparticles by a combination of evaporation of gold under a tilted angle followed by an etching step normal to the surface. 97,125 Similarly, the colloids themselves can be used to deposit the metal using colloids that contain metal nanoparticles or molecular metal complexes as precursor materials. 126,127 (iv) Capillary-assisted deposition of structures.…”

“…In addition to 3D photonic crystals, 2D colloidal monolayers can also be tuned to create many different optical materials and properties. For example, the monolayer can be used for shadow deposition to generate different shapes of deposited materials, 97,120,124,186 used as an etch mask to generate high aspect ratio structures with high order, 166,187,188 inverted/textured to create antireflective coatings for reducing the amount of reflected light from a substrate surface, 95 or deformed to generate structurally colored patterns on a substrate. 112 Interesting coupling effects can be observed between the photonic modes of an opal and the plasmonic modes of thin metals deposited on top of the crystal.…”

Surface Patterning with Colloidal Monolayers

“…This becomes obvious when realizing that many processes for complex structure construction take advantage of the substrate regions shaded by the colloids. [10,129,212] Once the particles completely lose their shapes, they can still be used for the construction of e.g. disc-like structures [213] or as etching masks for substrate patterning, [121,214] but any more complicated geometries (i.e.…”

A Feasible Routine for Large-Scale Nanopatterning via Nanosphere Lithography

“…In NSL, self-assembled nanospheres can be served directly as ordered nanostructures (Park et al, 1998) or a mask for the subsequent fabrication of nanostructures, which can be realized by deposition of desired materials, or by etching on desired substrates. A rich varieties of ordered nanostructures have been achieved by NSL, such as triangular structures (Winzer et al, 1996), metallic rings (Boneberg et al, 1997), nanopillars (Weeks et al, 2004), and multilayer with modified topography (Albrecht et al, 2005), nanodots (Chen et al, 2009;Weekes et al, 2007), 3D nanostructure (Zhang et al, 2007), discs (Hanarp et al, 2003) and nanoscale crescents (Gwinner et al, 2009;Retsch et al, 2009;Vogel et al, 2011). The shape, the size and the arrangement of ordered nanostructures can be readily controlled in combination of NSL and the subsequent deposition of desired materials (Haynes & Van Duyne, 2001;Zhang et al, 2007;Vogel et al, 2011).…”

“…Such BCCs may have potential applications in the fabrication of photonic crystal structures, theoretical models of phase transition, and templates of inverse structure (Kim et al, 2009). The arrangement of selfassembled nanospheres can be close-packed or non-close-packed (Vogel et al, 2011). In general, the self-assembled nanospheres are arranged in a hexagonal lattice.…”