Large-scale synthesis of a silicon photonic crystal with a complete three-dimensional bandgap near 1.5 micrometres

Abstract

Photonic technology, using light instead of electrons as the information carrier, is increasingly replacing electronics in communication and information management systems. Microscopic light manipulation, for this purpose, is achievable through photonic bandgap materials, a special class of photonic crystals in which three-dimensional, periodic dielectric constant variations controllably prohibit electromagnetic propagation throughout a specified frequency band. This can result in the localization of photons, thus providing a mechanism for controlling and inhibiting spontaneous light emission that can be exploited for photonic device fabrication. In fact, carefully engineered line defects could act as waveguides connecting photonic devices in all-optical microchips, and infiltration of the photonic material with suitable liquid crystals might produce photonic bandgap structures (and hence light-flow patterns) fully tunable by an externally applied voltage. However, the realization of this technology requires a strategy for the efficient synthesis of high-quality, large-scale photonic crystals with photonic bandgaps at micrometre and sub-micrometre wavelengths, and with rationally designed line and point defects for optical circuitry. Here we describe single crystals of silicon inverse opal with a complete three-dimensional photonic bandgap centred on 1.46 microm, produced by growing silicon inside the voids of an opal template of dose-packed silica spheres that are connected by small 'necks' formed during sintering, followed by removal of the silica template. The synthesis method is simple and inexpensive, yielding photonic crystals of pure silicon that are easily integrated with existing silicon-based microelectronics.

Evidence of the hexagonal columnar liquid-crystal phase of hard colloidal platelets by high-resolution SAXS

“…For instance, three-dimensional arrangements of spheres in colloidal crystals [1] might serve as photonic materials [2][3][4], intended to manipulate light. Colloidal particles with non-spherical shapes (such as rods and plates) are of particular interest because of their ability to form liquid crystals that might serve as templates for ordered porous materials.…”

Virus Nanoparticles Mediated Osteogenic Differentiation of Bone Derived Mesenchymal Stem Cells

“…Micro/nanofabrication techniques are required to enable the recapitulation of topographical cues in the cell niche in a controllable and reproducible fashion. Examples of these technologies are mechanical roughening,6 nano‐ and microindentation, and substrate‐templating using a well‐defined relief to impart topography with solvent‐casting, electrodeposition, chemical‐vapor depositions, or compression‐molding processes 7. These engineered micro/nanoscale topographical cues mimic the micro/nanoscale features in the physiological environment, which can be used to demonstrate how individual cues or the combination of topographical cues affect a particular cellular response.…”

Three-Dimensional Single Gyroid Photonic Crystals with a Mid-Infrared Bandgap

“…Three-dimensional photonic crystals offer opportunities to probe interesting photonic states such as bandgaps [1][2][3][4][5][6][7][8] , Weyl points 9,10 , well-controlled dislocations and defects [11][12][13] . Combinations of morphologies and dielectric constants of materials can be used to achieve desired photonic states.…”