Gold nanoantenna resonance diagnostics via transversal particle plasmon luminescence

Abstract

We perform two-photon excitation confocal experiments on coupled gold nanoantennas and observe time-integrated luminescence spectra that match plasmonic mode emission in the far-field. We show that the transversal particle plasmon mode can be excited, using excitation light that is cross-polarized with respect to the gold luminescence signal and therefore oriented along the long axis of the dipole gold antenna. We provide evidence for losses in polarization information from the excitation channel to the luminescence response due to the nature of the energy and momentum transfer. Finally, we map out the two-photon induced luminescence intensity profile for a fixed excitation wavelength λ and varying antenna arm length L.

Calculated thickness dependent plasmonic properties of gold nanobars in the visible to near-infrared light regime

“…This collective oscillation is known as a surface plasmon or simply a plasmon . Strong local-field enhancements, light absorption, and scattering all occur at a resonant incident wavelength, which can depend on the polarization of the light [1–3]. Due to their small volume, gold nanobars exhibit little radiation damping [1]; as a result, they show large local-field enhancement factors and large light scattering efficiency.…”

The Modulation Effect of Transverse, Antibonding, and Higher-Order Longitudinal Modes on the Two-Photon Photoluminescence of Gold Plasmonic Nanoantennas

“…In Figure , we plot the wavelength of the transverse resonances obtained in this work as a function of antenna width, which determines the transverse cavity length. Data points from previous work are also included. Error bars are added to Figure in order to indicate the uncertainty.…”

“…Error bars indicate the standard deviation within one antenna array. The simulated (black solid dot) and experimental (red solid triangle) data from ref are also included.…”

“…When gold nanoantennas are resonantly excited, the highly enhanced local field can promote the generation of two-photon photoluminescence (TPPL). − The TPPL of gold stems from sequential absorption of two photons followed by recombination of an electron in the sp band and a hole in the d band. , The absorption of the first photon regards an intraband transition and requires high field gradient to match the momentum. ,, Therefore, the generation of TPPL is sensitive to the local field intensity. Such sensitivity makes TPPL suitable for mapping the spatial distribution of antenna modes. , Since the TPPL from gold nanoantenna is broadband and strongly depolarized, it serves as an ideal near-field light source for the spectral analysis of antenna eigenmodes .…”

“…Recently, Wissert et al . have studied the influence of the antenna resonance on the TPPL spectrum. , They showed that the TPPL spectrum is shaped by the antenna’s fundamental bonding modes. Such modulation effect of antenna bonding modes has also been observed in the spectrum of one-photon photoluminescence from gold nanodisks. − These results suggest that the local energy of photoluminescence can relax into far-field emission via the antenna’s fundamental bright mode.…”