Surface-Enhanced Raman Scattering with Ag Nanoparticles Optically Trapped by a Photonic Crystal Cavity

We demonstrate a reusable and reconfigurable surface enhanced Raman scattering (SERS) platform by optically trapping Ag nanoparticles with a photonic crystal cavity integrated with a microfluidic chip. High-performance SERS is performed in a very reproducible manner, owing to the fact that Ag aggregates are produced by optical trapping in a controllable process that is monitored in real-time by the cavity resonance shift that occurs with the trapping of each additional nanoparticle.