Wave-vector analysis of plasmon-assisted distributed nonlinear photoluminescence along Au nanowires

Abstract

We report a quantitative analysis of the wave-vector diagram emitted by nonlinear photoluminescence generated by a tightly focused pulsed laser beam and distributed along Au nanowire via the mediation of surface plasmon polaritons. The nonlinear photoluminescence is locally excited at key locations along the nanowire in order to understand the different contributions constituting the emission pattern measured in a conjugate Fourier plane of the microscope. Polarization-resolved measurements reveal that the nanowire preferentially emits nonlinear photoluminescence polarized transverse to the long axis at close to the detection limit wave vectors with a small azimuthal spread in comparison to the signal polarized along the long axis. We utilize the finite-element method to simulate the observed directional scattering by using localized incoherent sources placed on the nanowire. Simulation results faithfully mimic the directional emission of the nonlinear signal emitted by the different portions of the nanowire.

Plasmon-Tunable Ag@Au Bimetallic Core–Shell Nanostructures to Enhance the Electrochemiluminescence of Quantum Dots for MicroRNA Sensing

“…From ECL-excited LSPR in Au NPs to QDs, the resultant energy transfer could increase nonradiative and radiative decay rates, which enhanced the ECL emission intensity of QDs in response to the LSPR of Au NPs. After that, two identical monometallic NPs-based plasmon-exciton couplings were reported, such as a symmetric homodimer composed of Au or Ag NPs. − When several metal NPs were close to each other, the hybridization plasma of SPR on the metal surface and gap plasma resonance among metal NPs exhibited a higher electromagnetic field intensity and surface plasmon coupling effect than a conventional single Au NP . For example, the plasmon coupling of Au NP dimers and Au nanodendrites achieved significant enhancement of ECL emission from CdS QDs. , However, for the majority of QDs, it is hard to realize a high spectral overlap with the plasmon enhancer.…”