Improvement of photostability using feedback from single-molecule fluorescence time trace

Abstract

Single-molecule fluorescence experiments are limited by photobleaching. Some photobleaching pathways involve photoexcitation from the triplet state. We report an optical feedback technique that yields a strong enhancement in the photostability of single fluorescent dye molecules. This is achieved by detecting in real time quantum jumps to the triplet state and then quickly switching off laser illumination while the molecule remains in its triplet state.