Surface Enhanced Raman Spectroscopy Using a Single Mode Nanophotonic-Plasmonic Platform

Abstract

We demonstrate the generation of Surface Enhanced Raman Spectroscopy (SERS) signals from integrated bowtie antennas, excited and collected by the fundamental TE mode of a single mode silicon nitride waveguide. Due to the integrated nature of this particular single mode SERS probe one can rigorously quantify the complete enhancement process. The Stokes power, generated by a 4-nitrothiophenol-coated antenna and collected into the fundamental TE mode, exhibits an 8 × 106 enhancement compared to the free space Raman scattering of a 4-nitrothiophenol molecule. Furthermore, we present an analytical model which identifies the relevant design parameters and figure of merit for this new SERS-platform. An excellent correspondence is obtained between the theoretically predicted and experimentally observed absolute Raman power. This work paves the way toward a new class of fully integrated lab-on-a-chip systems where the single mode SERS probe can be combined with other photonic, fluidic, or biological functionalities.