Plasmonic sensor: Towards parts-per-billion level sensitivity

We have developed a plasmonic gas sensing system using transmissive (metal hole array) and scattering (rough surface of Au film) plasmonic materials in an integrating sphere geometry. The combination of transmissive and reflective plasmonic materials significantly enhances the detection threshold by way of surface-enhanced infrared absorption. Here, we first investigate the individual sensing enhancement contributions for each of the plasmonic materials and reveal the path towards applications in high-sensitivity gas detection