Engineering single-molecule fluorescence with asymmetric nano-antennas

NIR fluorescence has shown great potential in bioscience, but low quantum-yield has largely impeded the research on most NIR fluorophores. Here, scientists in China use asymmetric plasmonic nano-antenna to drastically enhance NIR dye's single-molecule fluorescence intensity. The asymmetry provides an additional tuning parameter that offers new possibilities to modulate near-field and far-field properties of the plasmonic modes, thereby improving fluorescence without compromising molecule's photostability. This work provides a universal scheme for engineering NIR single-molecule fluorescence.