Benitez-Martin, CarlosLi, ShimingDominguez-Alfaro, AntonioNajera, FranciscoPérez-Inestrosa, EzequielPischel, UweAndréasson, Joakim2024-02-122024-02-122020-08-21http://hdl.handle.net/10668/16107http://hdl.handle.net/20.500.12105/18102The combination of two two-photon-induced processes in a Förster resonance energy transfer (FRET)-operated photochromic fluorene-dithienylethene dyad lays the foundation for the observation of a quartic dependence of the fluorescence signal on the excitation light intensity. While this photophysical behavior is predicted for a four-photon absorbing dye, the herein proposed approach opens the way to use two-photon absorbing dyes, reaching the same performance. Hence, the spatial resolution limit, being a critical parameter for applications in fluorescence imaging or data storage with common two-photon absorbing dyes, is dramatically improved.engVoRhttp://creativecommons.org/licenses/by/4.0/Attribution 4.0 International327995201423514854-1485810.1021/jacs.0c073771520-5126Journal of the American Chemical Societyopen access