Smart Photonics

Detecting the scattering process of individual nanoobjects using optical fibers is a promising fast, reliable and label-free detection scheme with strong potential in fields such as bioanalytics or disease diagnostics. Here we investigate the influence of single nanoobject scattering on the transmission of the fundamental mode of fiber tapers. We use an analytic equation for the key parameter related to particle induced scattering– the effective modal scattering area – and reveal optimal structural and spectral dependencies and limitations. As examples we determine the minimal detectable particle diameter of two sorts of nanoparticles, showing that silica tapers with diameter of the order of 500nm allow straightforward detection of plasmonic nanoparticles and polymer beads with diameters of 40nm and 150 nm, respectively.