Long range surface plasmon fluorescence spectroscopy

Abstract

Surface plasmon modes, resonantly excited at the two sides of an ultrathin (noble) metal layer in contact with two (nearly) identical dielectric media interact via the overlap of their electromagnetic fields resulting in two new coupled modes, i.e., a short range and a long range surface plasmon (LRSP), respectively. The authors demonstrate that both the enhanced optical field of the LRSP wave at the metal/dielectric interface as well as its increased (evanescent) penetration depth reaching farther into the analyte solution can be used for significant enhancements when using LRSP optics in a fluorescence spectroscopic mode of operation. They demonstrate this for the detection of fluorescence intensities from chromophore labeled proteins bound to the sensor surface matrix.