  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. 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 nm and 175 nm in the 1550 nm
wavelength band.
