Recent progress on photoluminescence from plasmonic nanostructures: Phenomenon, mechanism, and application

Photoluminescence（PL） from bulk noble metals arises from the interband transition of bound electrons. Plasmonic nanostructures can greatly enhance the quantum yield of noble metals through the localized surface plasmon. In this work,we briefly review recent progress on the phenomenon, mechanism, and application of one-photon PL from plasmonic nanostructures. Particularly, our recent efforts in the study of the PL peak position, partial depolarization, and mode selection from plasmonic nanostructures can bring about a relatively complete and deep understanding of the physical mechanism of one-photon PL from plasmonic nanostructures, paving the way for future applications in plasmonic imaging,plasmonic nanolasing, and surface enhanced fluorescence spectra.

In-plane coherent control of plasmon resonances for plasmonic switching and encoding

Considerable attention has been paid recently to coherent control of plasmon resonances in metadevices for potential applications in all-optical light-with-light signal modulation and image processing.Previous reports based on out-ofplane coherent control of plasmon resonances were established by modulating the position of a metadevice in standing waves.Here we show that destructive and constructive absorption can be realized in metallic nano-antennas through in-plane coherent control of plasmon resonances,which is determined by the distribution rule of electricalfield components of nano-antennas.We provide proof-of-principle demonstrations of plasmonic switching effects in a gold nanodisk monomer and dimer,and propose a plasmonic encoding strategy in a gold nanodisk chain.In-plane coherent control of plasmon resonances may open a new avenue toward promising applications in optical spectral enhancement,imaging,nanolasing,and optical communication in nanocircuits.

Near-Field Spot for Localized Light-Excitation of a Single Fluorescent Molecule

Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we investigate and numerically simulate a novel planar sub-wavelength 3-dimension(3D)structure,which is named as near-field spot.It enables the detection of a single molecule in highly concentrated solutions.The near-field spot can produce evanescent waves at the dielectric/water interface,which exponentially decay as they travel away from the dielectric/water interface.These evanescent waves are keys for the detection of fluorescently tagged single molecules.A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide.Additional degrees-of-freedom,however,can potentially supersede its performance.

Plasmonic evolution maps for planar metamaterials

Understanding the mode’s origin in planar metamaterials is fundamental for related applications in nanophotonics and plasmonics.For complex planar metamaterials,conventional analysis that directly obtains the final charge/current distribution of a mode is usually difficult in helping to understand the mode’s origin.In this paper,we propose a mode evolution method(MEM)with a core analysis tool,i.e.,plasmonic evolution maps(PEMs),to describe the mode evolution in several complementary planar metamaterials with designed plasmonic atoms/molecules.The PEMs could not only clearly explain a mode’s origin,but also reveal the role of a structure’s symmetry in the mode formation process.The MEM with PEMs can work as a simple,efficient,and universal approach for the mode analysis in different kinds of planar metamaterials.