A method to assess modifications of fluorophore radiative rate by plasmonic structures

We present a method for assessing radiative emission rates of the fluorophores by plasmonic metal structures by using fluorescence lifetime and cathodoluminescence measurements. By using this approach we identified and quantified the increased radiative rate of a Deep Purple fluorophore in inverted pyramidal pits of gold nanostructured arrays (Klarite) compared with the radiative rate of the same fluorophore on planar gold. This increased rate is attributed to the effect of localized surface plasmons preferentially concentrated in the pits of these arrays.