Giant and uniform fluorescence enhancement over large areas using plasmonic nanodots in 3D resonant cavity nanoantenna by nanoimprinting

Abstract

Using a new nanoplasmonic architecture and an optimized spacer, we observed the following: (a) the average fluorescence of an infrared dye (indocyanine green) is enhanced by 2970 fold uniformly (variation < 11%) over a large sample area and over a wide range of dye concentrations (380 to 380 000 molecule µm−2), laser excitation powers and laser beam sizes; and (b) for a single molecule placed at a ‘hot spot’, the fluorescence enhancement is 4.5 × 106 fold. The giant and uniform enhancements (orders of magnitude higher than before), plus easy and inexpensive large area fabrication ( > 4″ wafers), should open up wide applications.