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Lanthanide-doped upconversion nanoparticles (UCNPs) are appealing for light emitting applications because their high internal conversion efficiency facilitates the amplified spontaneous emission (ASE) under low pumping. In addition, the integration of photonic crystals and microcavities with optical quantum emitters provides a unique opportunity to manipulate their light emissions and generate coherent light sources for quantum photonics. Here, this work describes a two-dimensional (2D) plasmonic lattice of Al nanocone array (Al NCA), which can confine the light at the tip. Light confinement by the enhancement effect supports narrow linewidth resonances as optical feedback for the ASE of UCNPs doped with sensitizer Yb

Ceaselessly increasing demands for elaborate nanostructures prompt advanced structure fabrication with good practicability, especially, subwavelength ordered structures in simple lattices even in superlattices over a large area, namely, large-scale photonic lattices, in which lattice arrangement, geometry, and components of unit cells are key factors for their macroscopic optical properties. Moreover, exciting properties always occur at high symmetry points of the lattice; therefore, straightforward modulation of symmetry points over a large area is very important for the investigation and application of photonic lattices. Here, this work establishes a lithography-free approach of undervoltage oxidation (UVO) for regulating high symmetry points in the reciprocal space of a dielectric alumina superlattice. Embedding subunit cells at high symmetry points Γ (M) result in the degenerate energy changing from 1.34 eV (924.6 nm) to 1.87 eV (662.6 nm) under normal excitation at the Γ point, and the degeneracy lifting under off-normal excitation along the Γ-X high symmetry orientation. Furthermore, systematic characterizations of the alumina membrane are presented to learn its dynamic evolution of the morphology on a centimeter scale, and the pore array changes from a hierarchical period to a form of hexagonal close packing, especially at Γ and M points of the square lattice. Therefore, the reported lithography-free alumina-based nanofabrication offers an ability for varying the spatial structure at high symmetry points of photonic lattices, which is of great significance in the fields of nanomanufacturing and has great potential to bring about preferable performances in nanodevices.

Surface plasmon excitations in metallic hole arrays have been extensively studied in the context of light–matter interaction, since the generated Bloch surface plasmon polariton (Bloch-SPP) exhibits unique properties of nanoscale light confinement, near-field enhancements, and long-range metal surface propagation. In this work, we experimentally demonstrate a plasmonic device that exhibits highly directional emission in visible light; using Ag film with a thickness of 100 nm deposited on a subwavelength porous alumina array as a plasmonic cavity, four-level rhodamine 6G (R6G) is selected as the gain material. It is suggested that a Bloch-SPP with high diffraction orders on a Ag nanohole array can generate a strong local electric field and a high Purcell factor at a nanohole edge. Moreover, directional five-fold enhanced amplified spontaneous emission (ASE) with polarization dependence is observed under a low threshold of 199.9 W/cm2 in the visible light region, which comes from the optical feedback provided by the 2D periodic nanohole array. This work opens up a wide range of applications for real-time tunable wavelength, controlled multimode laser, fluorescence detection, etc.

Strong light-matter coupling manifested by Rabi splitting has drawn considerable interest owing to its fundamental significance for impressive interaction enhancement in the fields of ultrafast active plasmonic devices and quantum information. In this paper, we investigate the coherent optical properties of a plasmonic system consisting of periodic metal nanoparticle arrays covered by a WS

Structural color has been studied through various methods due to its distinguished features of stability, durability, high information storage density and high integration. However, the artificial structural color samples do not exhibit superior performance in color saturation and low angular dependence. Here, we present an approach to acquire additive reflective color based on a metal–dielectric–metal (MDM) stack. The upper layer composed of Ag particles is perforated in a hexagonal arrangement which profits from the dielectric anodic aluminium oxide (AAO) membrane. The size and shape of the Ag particles are getting inhomogeneous as the deposition thickness of the upper layer increasing, which expands the desired absorption range of surface plasmons. The residual non-anodized Al foil serves as a highly reflective substrate for efficient color presenting through the thin-film interference in this plasmonic MDM system. As a result, the color gamut area of this MDM stack is extended 8 times in CIE chromaticity coordinates. Finally, a wafer-scale (diameter of 83 mm) badge of Harbin Engineering University (HEU) with highly saturated colors and a pattern characterized with low angle-dependent property (up to 60°) are presented, which exhibit promising prospects in commercial coloring and imaging.

Strong light–matter coupling manifested by Rabi splitting has drawn considerable interest owing to its fundamental significance for impressive interaction enhancement in the fields of ultrafast active plasmonic devices and quantum information. In this paper, we investigate the coherent optical properties of a plasmonic system consisting of periodic metal nanoparticle arrays covered by a WS2 thin film of atomic layer thickness. The coupling factor, energy splitting, and temporal dynamics of this coherent coupling phenomenon are quantitatively revealed by finite-difference time-domain (FDTD) simulation and a full quantum mechanical model proves that the exciton behavior of the fermionic quantum emitter WS2 is carefully modulated by bosonic surface lattice resonances. This work may pave the way for coherent modulation of polariton and plasmon devices and can potentially open up diverse exciting possibilities like nanoscale light sources, single-photon emitters, and all-optical transistors.

Arrays of metal–dielectric–metal (MDM) multilayer nanostructure can support various kinds of plasmonic modes including in-plane (IP) localized/delocalized surface plasmons or lattice resonances, photonic waves, as well as out-of-plane (OP) plasmon modes. Hybridization between different modes offers rich physics such as lasing, sub- and super-radiant modes, and efficient light absorption. While interplays between different sets of in-plane modes have been intensively investigated, the interaction between in-plane and out-of-plane modes is rarely explored. Here, we propose a MDM nanostructure with 2D nanocylinder array and study in detail the strong coupling between the in-plane photonic modes at the dielectric layer and the out-of-plane plasmon modes excited at the cylinder sidewalls. We demonstrate the strong coupling between the localized second-order IP mode and the first-order OP mode with a Rabi splitting up to 250 meV in the near-infrared region. A new IP mode arising from the radiative field can induce another kind of strong coupling with OP modes as the cylinder radius is larger than 98 nm. The underlying physics within this plasmon–photon system is quantitatively revealed by the coupled oscillator model and calculated E-field distribution. The proposed MDM system provides a good platform for investigating multimode coupling and nano-optics devices.