Surface label-free sensing by means of a fluorescent multilayered photonic structure

A fluorescent dielectric multilayer is exploited for label-free sensing in aqueous micro-environment. Fluorescence is laser-excited and collected through prism-coupling to a surface electromagnetic mode, also known as Bloch surface waves (BSW) localized at the interface between the multilayer and the outer aqueous medium. By detecting the spectral changes of the BSW-coupled light emission due to an external perturbation of the refractive index (Delta n), a sensitivity of similar to 2500 nm/RIU and a limit of detection down to Delta n similar to 3 x 10(-6) are obtained. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4754615]