Far-field modulation of fluorescence decay rates in pairs of oriented semiconducting polymer nanostructures

We report on the observation of far-field dipole-dipole coupling in pairs of uniformly z-oriented polymer nanostructures manifested as a fluorescence lifetime modification (both enhancement and suppression relative to isolated particles) modulated by interparticle separation. The observed oscillatory modulation in the fluorescence decay rate as a function of interparticle distance (ranging from 200 to ≈2000 nm) results from modification of the vacuum field at the position of the probe dipole by the presence of the second radiating dipole. These results provide observation of a dipole-dipole interaction in the “inductance” interparticle distance scale between the near field (≈200 nm) and far field (>500 nm), important for the realization of efficient active nanophotonic devices.