Beaming Elastic and SERS Emission from Bent-Plasmonic Nanowire on a Mirror Cavity

TL;DR

This paper demonstrates the experimental realization of beaming elastic and SERS emission from a bent plasmonic nanowire on a mirror cavity, combining polarization-resolved imaging and numerical simulations to analyze emission directionality.

Contribution

It introduces a novel bent-nanowire on mirror cavity system for controlled beaming of elastic and SERS emission, supported by experimental and numerical analysis.

Findings

Elastic scattering directionality: 16.2 dB

SERS emission directionality: 12.5 dB

Enhanced Raman emission using molecular orientation and cavity fields

Abstract

We report on the experimental observation of beaming elastic and surface enhanced Raman scattering (SERS) emission from a bent-nanowire on a mirror (B-NWoM) cavity. The system was probed with polarization resolved Fourier plane and energy-momentum imaging to study the spectral and angular signature of the emission wavevectors. The out-coupled elastically scattered light from the kink occupies a narrow angular spread. We used a self-assembled monolayer of molecules with a well-defined molecular orientation to utilize the out-of-plane electric field in the cavity for enhancing Raman emission from the molecules and in achieving beaming SERS emission. Calculated directionality for elastic scattering and SERS emission were found to be 16.2 and 12.5 dB respectively. The experimental data were corroborated with three-dimensional numerical finite element and finite difference time domain based numerical simulations. The results presented here may find relevance in understanding coupling of emitters with elongated plasmonic cavities and in designing on-chip optical antennas.