Fluorescence nanoscopy by ground-state depletion and single-molecule return

Abstract

We introduce far-field fluorescence nanoscopy with ordinaryfluorophores based on switching the majority of them to ametastable dark state, such as the triplet, and calculating theposition of those left or those that spontaneously returned to theground state. Continuous widefield illumination by a single laserand a continuously operating camera yielded dual-color imagesof rhodamine- and fluorescent protein–labeled (living) samples,proving a simple yet powerful super-resolution approach.