A combined enhanced-fluorescence and label-free imaging instrument

Photonic crystals have previously been shown to enhance fluorescence output of surface-bound dyes by two orders of magnitude and to enable sensitive label-free biomolecular detection. In this work we describe the design and characterization of a microscope capable of generating both label-free and enhanced-fluorescence images on engineered photonic crystal surfaces. We demonstrate 328x fluorescence enhancement, 41x signal-to-noise improvements, and a reduction in the detection limit of a protein-conjugated fluorophore by over two orders of magnitude. We also characterize the resolution of enhanced fluorescence and label-free imaging to be submicron and 3 microns, respectively.