Here we propose a scheme utilizing
the double plasmon modes of
gold nanorod (GNR) to efficiently enhance the fluorescence of surrounding
emitters. The transversal and longitudinal surface plasmon resonance
(TSPR and LSPR, respectively) modes of GNR are simultaneously utilized
to enhance the excitation and emission efficiency, respectively. To
demonstrate the idea, GNRs coated with an Oxazine-725 dye molecule-doped
silica shell are employed. For comparison, gold nanospheres with the
same shell are also studied, of which the single plasmon resonance
mode matches only with the excitation wavelength of Oxazine-725. The
experimental results, in agreement with theoretical simulations using
the discrete dipole approximation method, successfully demonstrate
the efficient excitation and emission enhancement of fluorescence
assisted by the double SPRs of GNRs.
Flexible microdisk whispering-gallery-mode (WGM) resonators with high quality factors were achieved through the controlled assembly of organic materials with an emulsion-solvent-evaporation method. The high material compatibility of the assembled microdisks enabled us to realize low-threshold WGM lasers by doping with organic dyes as gain media. Furthermore, the emulsion-assisted self-assembly provided a strategy for the one-step fabrication of microwire-waveguide-connected microdisk heterostructures, which can be utilized for the efficient output of the isotropic WGM lasers from the coupled waveguides. We hope that these results will pave an avenue for the construction of new types of flexible WGM-based components for photonic integration.
We report on the efficient surface plasmon amplification by stimulated emission of radiation (spaser) from a gold nanorod coated with proper gain media. Numerical simulations show that the threshold of the nanorod-based spaser is nearly 1 order of magnitude lower than that of the core-shell nanosphere, which is verified by analysis with electrostatic theory. Furthermore, it is found that the nanorod-based nanosystem possesses unique optical properties such as wavelength tunability and polarization sensitivity.
We report on direct observation of amplified spontaneous emission (ASE) of surface plasmon polaritons (SPPs) at the interface of a silver film and a gain medium. Based on a typical Kretschmann configuration incorporated with Rhodamine 6G molecules, the growing ASE spectra of SPPs have been clearly identified by carefully conducting a pump-dependent angle-resolved spectral measurement. Spectral narrowing effects induced by the SPP amplification are also demonstrated. The observed phenomena are helpful in understanding the fundamental interactions between SPPs and gain medium, which could enable wide applications on plasmonic sources and sensors. V
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