Abstract

Surface-enhanced Raman spectroscopy(SERS) is a widely studied technique to enhance the Raman signal of molecules. The high electric field near SERS substrate and the large number of optical density of states, enable us to detect single molecule and their chemical specification. These high electric field locations are called hotspots which can be achieved in many ways: one interesting way to harness the electric fields of a nanocavity. Nanocavity assisted SERS(Surface-enhanced Raman Scattering) is studied in the context of the intensity enhancement, strong coupling, sensing capability etc. An important aspect of Cavity assisted SERS which has not been studied extensively is the wavevector distribution of the emission. Here we are studying the wavevector distribution of SERS emission from plasmonic nanowire-nanoparticle junction cavity using Fourier microscopy. The emission is confined to a narrow range of wavevectors perpendicular to the axis of the wire. This emission also excite multiple guided modes of the nanowire which has been imaged using leakage radiation Fourier microscopy. Further, we have characterized the polarization signature of the emission in the Fourier plane. The results are modeled with finite element method based numerical simulation.

© 2019 The Author(s)

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