Fluorescence-based detection of chemically tagged biomolecules is the most widely used technique in life science research and diagnostic assays and has been used in applications including DNA sequencing, DNA and protein microarrays, immunoassays, and cell imaging. Despite the sensitivity afforded by this approach, the detection limit must be further improved to observe/quantify the analytes at lower concentrations. We have applied photonic crystal surfaces in various settings to enhance the fluorescence intensity and to extend fluorescence-based assays to lower concentrations