Surface Enhanced Fluorescence by Plasmonic Nanostructures

The optically generated collective electron density waves on metal-dielectric boundaries known as surface plasmons have been of great scientific interest since their discovery. Being electromagnetic waves on noble nanostructure’s surface, surface plasmons resonance can strongly enhance the electromagnetic field. These strong electromagnetic fields near the metal surfaces have been used in various applications like surface enhanced spectroscopy, plasmonic lithography, plasmonic trapping of particles and plsmonic catalysis etc. Resonant coupling of localized surface plasmons to fluorescent emitters can strongly modify the emitted intensity, the angular distribution and the polarization of the emitted radiation and even the speed of radiative decay, which is so-called surface/metal enhanced fluorescence (MEF/SEF). In this chapter, we illustrate current progress in design of metallic nanostructures for efficient fluorescence signal amplification that utilizes propagating and localized surface plasmons, and also some critical parameters in SEF, such as spacer, wavelength dependence effect are also discussed.