Surface enhanced Raman spectroscopy using a single mode nanophotonic-plasmonic platform

Abstract: Surface Enhanced Raman Spectroscopy (SERS) is a well-established technique for enhancing Raman signals. Recently photonic integrated circuits have been used, as an alternative to microscopy based excitation and collection, to probe SERS signals from external metallic nanoparticles. However, in order to develop quantitative on-chip SERS sensors, integration of dedicated nanoplasmonic antennas and waveguides is desirable. Here we bridge this gap by demonstrating for the first time the generation of SERS signals from integrated bowtie nanoantennas, excited and collected by a single mode waveguide, and rigorously quantify the enhancement process. The guided Raman power generated by a 4-Nitrothiophenol coated bowtie antenna shows an 8 x 10^6 enhancement compared to the free-space Raman scattering. An excellent correspondence is obtained between the theoretically predicted and observed absolute Raman power. This work paves the way towards fully integrated lab-on-a-chip systems where the single mode SERS-probe can be combined with other photonic, fluidic or biological functionalities.