Optical Detection of Single Nanoparticles With a Subwavelength Fiber-Taper

A nanoparticle detection scheme with single particle resolution is presented. The sensor contains only a taper fiber, thus offering the advantages of compactness and installation flexibility. The sensing method is based on monitoring the transmitted light power which shows abrupt jumps with each particle binding to the taper surface. The experimental validation of the sensor is demonstrated with polystyrene nanoparticles of radii 120 and 175 nm in the 1550-nm wavelength band.