Therefore, these methods provide exciting possibilities for controlling the interaction between photonic modes of microcavity structures and plasmonic modes of the highly polarizable nanoparticles for nano-/micrometer-scale optical applications. Furthermore, structures with geometrically well-defined 3D crystal habits ( 10), when locked into the solid state via silica embedding procedures ( 13), open up potential applications in the field of optics. Importantly, 3D counterparts of these 1D and 2D architectures can lead to interesting properties such as higher microcavity Q factors ( 2), 3D angular emission dependence, and stronger mode confinement ( 7).ĭNA-guided nanoparticle colloidal crystallization provides remarkable control over the assembly of nanoparticles into superlattices ( 9, 10), enabling the deliberate tailoring of crystal symmetry ( 9), lattice constant ( 11), and particle composition ( 12). However, most of the plasmonic microcavities have been limited to 1D or 2D microcavity geometries and plasmonic mode confinement ( 7) (metallic nanostructures) due to limitations in fabrication methods ( 6, 8). Such hybrid photonic structures are desirable because they can lead to high Q factors and strong light confinement within a single architecture, significantly enhancing light–matter interactions by a large cavity figure of merit, Q/ V. These plasmonic microcavities exploit two different aspects of the architectures simultaneously: guided optical modes that resonate or scatter light (via the microcavity geometry) and near-field–driven optical confinement (via the metallic nanostructure). In recent years, researchers have developed strategies for incorporating plasmonic nanostructures into microcavity structures to enhance light–matter interactions via strong light confinement (small mode volume, V), resulting in materials that are capable of plasmon lasing ( 5– 7). They have been used to understand phenomena in cavity quantum electrodynamics ( 1, 2), and to enable molecular sensing ( 3) and lasing ( 4) technologies.

Microcavities are important photonic architectures that can be used to couple dipole emitters with optical modes and enhance light–matter interactions typically with long cavity lifetimes (high Q factors). The unique ability to control surface plasmon/exciton interactions within such superlattice microcavities will catalyze studies involving quantum optics, plasmon laser physics, strong coupling, and nonlinear phenomena. The ability to control dye position with subnanometer precision allows one to systematically tune plasmon–excition interaction strength and decay lifetime, the results of which have been supported by electrodynamics calculations that span length scales from nanometers to micrometers. At the nanoscale, the interaction between the dye dipoles and surface plasmons can be finely tuned by coupling the dye molecules to specific sites of the DNA particle-linker strands, thereby modulating dye–nanoparticle distance (three different positions are studied). At the micrometer scale, the anisotropic rhombic dodecahedron crystal habit couples with photonic modes to give directional light emission. Encapsulation in silica allows one to create robust architectures with the plasmonically active particles and dye molecules fixed in space. DNA-guided nanoparticle colloidal crystallization allows for the formation of micrometer-scale single-crystal body-centered cubic gold nanoparticle superlattices, with dye molecules coupled to the DNA strands that link the particles together, in the form of a rhombic dodecahedron. Three-dimensional plasmonic superlattice microcavities, made from programmable atom equivalents comprising gold nanoparticles functionalized with DNA, are used as a testbed to study directional light emission.

Particle playground emit over distance