Metal single-nanowire plasmonic sensors.

We demonstrated a general approach for plasmonic sensing using metal single nanowires based on an evanescent coupling technique, where light was efficiently launched into and picked up from the metal nanowires using silica fiber tapers. A high amplitude sensitivity of ~13 dB to 1.2% hydrogen was obtained using palladium-coated Au nanowires for hydrogen sensing, and a fast response of ~5 ms was obtained using a polyacrylamide film-supported Ag nanowire for relative humidity sensing. Our results may help develop metal nanowire-based plasmonic sensors.