Fluorescent dyes as a probe for the localized field of coupled surface plasmon-related resonances - art. no. 075406

The fluorescence light of Cy5 dye molecules in the vicinity of a metal grat ing is studied for varying directions of both the exciting and the emitted light. A different angular dependence of the intensity of the emitted light is observed for different directions of excitation. Model calculations tha t take into account the localization of the electrical field of grating-cou pled surface plasmon-related resonances are in good agreement with the expe rimental observations. In addition, the spatially inhomogenous photobleachi ng of the dye in the field of the coupled resonances is experimentally obse rved. These results can be viewed both as a way to use chromophores as mole cular probes for the localized electrical near field of coupled surface pla smon-related resonances and as a way to manipulate dye molecules on a submi cron scale.