Plasmonic enhancement of fluorescence was investigated for its employment in sensing applications as well as in the design of low-cost fluorescence sensing devices. Two different plasmonic effects were considered, metal-enhanced fluorescence (MEF) and surface plasmon-coupled emission (SPCE). MEF occurs when the free space fluorescence condition is modified with sub-wavelength metallic nanoparticles resulting in an enhanced quantum yield and a decreased fluorescence lifetime. Another near-field plasmonic phenomenon is SPCE where the plasmon-coupling results in highly directional, polarized fluorescence emission.

The first aspect of the research was to explore potential sensing applications incorporating SPCE. First, the high sensitivity of the phenomenon was examined through the detection of a monolayer of green fluorescent protein as evidenced by the visible emission ring. Secondly, a potential SPCE sensing application was investigated based on the fluorescence quenching of a monolayer of a ruthenium complex by oxygen. Due to the ultra-thin sensing layer, the observed response time was less than 0.5 seconds. In addition, despite the reduction in lifetime created by the metal film, lifetime-based sensing was also demonstrated in correlation with typical intensity-based measurements.

Following the establishment of SPCE as a possible fluorescence sensing detection technique, investigations were performed leading to the development of a low-cost sensing device that incorporates SPCE for high sensitivity. First, low-cost excitation of SPCE via a light-emitting diode was observed. Next, solution-based silver deposition was studied as an alternative technique for the production of SPCE slides. The SPCE from these slides was similar to that observed from conventional vapor-deposited slides. Also, a SPCE detection scheme was designed and tested leading to a 500-fold enhancement of the free space signal with an almost 35-fold increase in the signal-to-noise ratio.

In addition to SPCE, the benefits of MEF can also be used to improve current fluorescence-based assays. In this case, the enzyme-linked immunosorbent assay method for protein quantification was modified by the presence of sub-wavelength metallic nanoparticles resulting in faster assay times with similar sensitivity.

In summary, the use of plasmonic structures to enhance fluorescence was demonstrated allowing for highly sensitive, rapid detection of analytes.