Metamaterials concept has been under extensive development over the past two decades and has been proven to be beneficial for a wide range of practical applications in both microwave and optical spectral ranges. In particular, it is commonly used for tailoring light-matter interactions on nanoscale. While many different approaches towards metamaterials fabrication exist, most of them are limited to “top-down” concept, including but not limited to lithographic methods, like photolithography, e-beam and nanoimprint lithography. On the other hand, the “bottom-up” chemical self-assembly techniques offer several distinctive advantages like throughput and cost-effectiveness, allowing large-scale production of composites. Here a novel metamaterial platform, based on mesoporous vaterite particles (further referred to as cargoes) is proposed and demonstrated. Controllable doping of micron and sub-micron scale dielectric hosts with metal nanoparticles enables tuning effective plasma frequency of new composites and, as the result, allows tailoring properties of collective localized plasmon resonances that they support. Furthermore, newly developed fabrication protocols enable introducing active materials (e.g. dyes and colloidal quantum dots) within vaterite cargoes and tailor their emission properties. Introduction of high concentration of active materials into compound particles allows compensating material losses in the medium with gain. Moreover, by coating the surface of the particles with passivating agents, it is possible to achieve long-term stability of such compound cargos in different types of solvents. Both unrestricted three-dimensional motion (compared to two-dimensional trapping of metallic particles) and rotation by circularly polarized trapping beams were demonstrated. Theoretical, numerical and experimental studies of those novel composites with beforehand mentioned properties will be presented. The vaterite-based metamaterial platform paves a way to new fundamental investigations and enables to introduce concepts of ultra-bright controllably floating imaging agents for relevant bio-medical applications.
We demonstrate a novel process for selective binding of single semiconductor core-shell quantum dots (QDs) to transparent all-dielectric (glass) substrates with nanoscale resolution. This is accomplished by defining a mask via electron-beam lithography (EBL) followed by functionalization of only the exposed areas of the substrate with a heterobifunctional linker, while applying a binding inhibitor to all other areas. Single QD blinking is clearly observed for several QD functionalized sites. Our approach is compatible with standard two-step EBL nanofabrication schemes and it does not rely on the presence of metals, making it suitable for coupling QDs to all-dielectric nanoresonators.
We report on the fabrication of inverted Yablonovite-like three-dimensional photonic crystals by nonlinear optical
nanolithography based on two-photon polymerization of a zirconium propoxide hybrid organic-inorganic material with
Irgacure 369 as photo-initiator. Advantage of this material is ultra-low shrinkage that guaranty high fabrication fidelity.
Images of the fabricated structure are obtained with a scanning electron microscope. The photonic crystal consists of
three sets of nearly cylindrical structural elements directed along the three lattice vectors of the fcc lattice and cross each
other at certain angles to produce inverted Yablonovite geometry. To investigate photonic properties of the inverted
Yablonovite structures, we calculate the photonic band structure for ten lowest-frequency electromagnetic modes. In
contrast to the direct Yablonovite structure that has a complete photonic band gap between the second and third bands,
we find no complete photonic band gaps in the inverted Yablonovite lattice. This situation is opposite to the case of fcc
lattice of close-packed dielectric spheres in air that has a complete photonic band gap only for the inverted geometry.