# Self-Organized Conductive Gratings of Au Nanostripe Dimers Enable Tunable Plasmonic Activity
## 1 Introduction  
Plasmonic nanoantennas have collected a strong research and technological interest within the last decade, due to their unique capability to achieve resonant light scattering and near-field confinement at the nanoscale level, enabling novel functionalities in nano-optics, biosensing and energy harvesting [1; 2; 3; 4; 5; 6; 7; 8]. In particular, the possibility to tune localized plasmon resonances of subwavelength noble metal nanostructures over a broadband spectrum has been investigated for the selection and local amplification of weak molecular signals in linear and/or nonlinear optical spectroscopies [2; 6; 7; 8; 9; 10; 11; 12]. One possibility for the nanofabrication of highly sensitive biosensing templates and nanodevices is given by lithographic techniques, which allow the increased complexity of the individual meta-atoms, controlling the shape and/or the inter-particle spacing at the nanoscale level [13; 14; 15; 16]. The lithographic design of complex in-plane nanoantennas has been exploited to achieve strong efficiency in plasmon-enhanced optical spectroscopies active over different spectralranges, such as Surface Enhanced Raman Scattering (SERS) [17; 18; 19; 20; 21] and Surface Enhanced Infrared Absorption (SEIRA) spectroscopy [11; 22; 23; 24]. Despite the high degree of control provided by the lithographic methods, the reduced patterned areas, limited at the micrometric scale, and/or the multi-step, time-consuming processes strongly hinder the effective application of optimized plasmonic metasurfaces in cost-effective optoelectronic, biosensing and/or diagnostic devices [25; 26]. On the other hand, self-assembled nanofabrication methods [27; 28; 29] allow the large-area functionalization of surfaces, but are generally characterized by low homogeneity and the limited possibility of tailoring the nanostructure's shape.  
Here, large-area (cm\({}^{2}\)) highly ordered plasmonic templates are prepared by a novel maskless self-organized nanofabrication method. A nanoscale wrinkling instability in glasses induces quasi-1D nanopatterned templates, which enable the confinement of out-of-plane tilted plasmonic nanostripes and/or nanostripe dimers [30]. The method allows the easy tailoring of the nanostripes' morphology, and thus the tuning of their localized plasmon resonances across the visible (VIS) and near-infrared (IR) spectrum. Most interestingly, our technique enables the engineering of Au-SiO\({}_{2}\)-Au nanostrip dimers supporting hybridized plasmon resonances [31]. A strong sub-radiant near-field confinement can therefore be achieved by exciting the hybridized magnetic dipole mode, with the additional possibility to tune its resonance over a broadband VIS and near-IR spectrum. The possibility to effectively tailor the nanoscale morphology--thus achieving a fine tuning of the optical response in a cost-effective way--combined with the superior plasmonic near-field confinement and light scattering properties, opens a variety of applications for these templates in optical spectroscopy, biosensing, optical microscopy and nonlinear optics.