A hybrid plasmonic whispering gallery mode sensor for single bionanoparticle detection

\ Our hybrid plasmonic whispering gallery mode biosensor has recently demonstrated detection and characterization of the smallest known RNA virus. A gold nanoparticle affixed to the resonator surface acts like a nanoscopic antenna, enhancing locally the electric field within the cavity mode. When a target analyte binds with this nanoscopic antenna the result is an enhanced response (spectral shift) of the resonator system to the binding event. We have observed shift enhancements similar to 70x over the response of the bare resonator, thereby permitting the detection and characterization of all known viral particles and even some large protein molecules.