Enhanced fluorescence emission using a photonic crystal coupled to an optical cavity

All fluorescent assays would benefit from greater signal-to-noise ratios (SNRs), which enable detection of disease biomarkers at lower concentrations for earlier disease diagnosis and detection of genes that are expressed at the lowest levels. Here, we report an approach to enhance fluorescence in which surface adsorbed fluorophore-tagged biomolecules are excited on a photonic crystal surface that is coupled to an underlying Fabry-Perot type cavity through a gold mirror reflector beneath the photonic crystal. This approach leads to 6x increase in signal-to-noise ratio of a dye labeled polypeptide compared to ordinary photonic crystal enhanced fluorescence. (C) 2013 AIP Publishing LLC.