Leakage radiation microscopy (LRM) is extended to the characterization of dye doped planar polymer waveguide modes (WMs) rather than surface plasmon polaritons (SPPs). We mainly focus on how to measure the propagation lengths of the WMs excited by the fluorescence from the dye molecules. Numerical simulations are also carried out to calculate the propagation lengths of these modes and are consistent with experimental results.

In this paper, we will demonstrate that excited dye molecules can be used to launch the plasmonic Bloch waves (PBWs) propagating at multi-metal-dielectric interfaces. The properties of the PBWs, such as wavevectors, propagating bands, the interface and grating period effect, were characterized by a leakage radiation microscope. Theoretical simulations were also carried out to reveal the properties of the PBWs and were consistent with the experimental results. What is more, experimental results reveal an interesting phenomenon: the PBWs launched by the excited dye molecules present different optical behaviors from those launched by far-field laser beams through attenuated total reflection. The mechanism of this difference was analyzed based on the energy conversion between the optical near-field and far-field. Our work provides a new way to launch the PBWs. Further, the coupling between the dye molecules and PBWs also demonstrates a new method to manipulate the fluorescence emission from random to controllable.