Observation of Surface Plasmon-coupled Directional Fluorescence Using Thin Iron Films

The observation of surface plasmon-coupled directional fluorescence (SPCDF) on thin iron films was presented. SPCDF from thin iron films was p-polarized with a directional emission angle of 70 degrees. Fluorescein and meso-tetra(4-sulfonatophenyl)porphine(TPPS) were used as a model system of dual fluorophores. Using 25 nm thin iron films, the SPCDF signals of the two fluorophores were observed at a fixed angle just by one scan. The SPCDF signals of Fluorescein and TPPS added to whole blood were identified clearly, eliminating the background interference of blood effectively. Thin iron films have been proven to be new materials for SPCDF detection, promoting a new mode to observe the enhanced fluorescence signals of different fluorophores by one scan. They should be useful for tracking the labled systems of multi-fluorophores in biological applications.