Frontiers of light manipulation in natural, metallic, and dielectric nanostructures

Abstract

The ability to control light at the nanoscale is at the basis of contemporary photonics and plasmonics. In particular, properly engineered periodic nanostructures not only allow the inhibition of propagation of light at specific spectral ranges or its confinement in nanocavities or waveguides, but make also possible field enhancement effects in vibrational, Raman, infrared and fluorescence spectroscopies, paving the way to the development of novel high-performance optical sensors. All these devices find an impressive analogy in nearly-periodic photonic nanostructures present in several plants, animals and algae, which can represent a source of inspiration in the development and optimization of new artificial nano-optical systems. Here we present the main properties and applications of cutting-edge nanostructures starting from several examples of natural photonic architectures, up to the most recent technologies based on metallic and dielectric metasurfaces.

Organismal Design and Biomimetics: A Problem of Scale

“…(2) structural colours, created by the selective reflection or coherent/incoherent scattering of the incident light impinging on highly structured and unstructured multilayer or hierarchical architectures; and (3) bioluminescence, the production and emission of light as a result of biochemical reactions using light-emitting molecules and enzymes [141,144,145]. Each source utilizes principles that function at different scales (especially at a nano-and microscale) and are mainly based on intra-and interspecific perceptions.…”

“…Presently, many of these organismal optical strategies are applied at a nano-and microscale, e.g., nanotechnology and new materials, to a macroscale, e.g., airplanes and ships. Technological advances have led to the invention of new materials (i.e., metamaterials) and methods allowing light manipulation, even at the nanoscale, in turn influencing the range of optical products that can be designed [145,149,150]. Light control and processing play a key role in telecommunications, imaging, sensing, biomedicine, energy harvesting and many other fields [151].…”

“…The simplest photonic nanostructure in biological systems was detected in iridoviruses [162]. These viruses self-assemble in paracrystalline arrays within the cells of infected organisms, causing optical iridescence arising from multiple Bragg scattering [145]. Biological nanostructures, characterized by multilayer arrangements, acting as selective reflectors are quite diffused in several floral or faunal species.…”

“…Biological nanostructures, characterized by multilayer arrangements, acting as selective reflectors are quite diffused in several floral or faunal species. These biostructures determine the structural colours, which do not depend on pigments but rather on their geometrical pattern and refractive index contrast, with respect to the surrounding environment [145,163]. Moreover, the combination of multilayer interference with coherent scattering and/or diffraction can contribute to structural colouration and iridescence [164].…”

Plasmonic Nanosensors: Design, Fabrication, and Applications in Biomedicine

“…In recent years, great advances in nanotechnology have largely found applications in the field of biomedicine. In this context, the optical properties of metallic nanomaterials such as gold (Au) and silver (Ag) nanoparticles (NPs) have been exploited to produce nanodiagnostic and nano-therapeutic smart systems, which are simple, exhibit fast response times, and are relatively low-cost [1][2][3][4][5][6]. Physics, engineering, chemistry, and material science have been combined with biology, biotechnology, and medicine to produce biomedical devices that convert biological and/or biochemical signals into electrical ones through electrical, optical, electrochemical, or piezoelectric transducers [7][8][9][10][11].…”