title: Pushing the Photon Limit: Nanoantennas Increase Maximal Photon Stream and Total Photon Number.
abstract: Nanoantennas are well-known for their effective role in fluorescence enhancement, both in excitation and emission. Enhancements of 3-4 orders of magnitude have been reported. Yet in practice, the photon emission is limited by saturation due to the time that a molecule spends in singlet and especially triplet excited states. The maximal photon stream restricts the attainable enhancement. Furthermore, the total number of photons emitted is limited by photobleaching. The limited brightness and observation time are a drawback for applications, especially in biology. Here we challenge this photon limit, showing that nanoantennas can actually increase both saturation intensity and photostability. So far, this limit-shifting role of nanoantennas has hardly been explored. Specifically, we demonstrate that single light-harvesting complexes, under saturating excitation conditions, show over a 50-fold antenna-enhanced photon emission stream, with 10-fold more total photons, up to 10(8) detected photons, before photobleaching. This work shows yet another facet of the great potential of nanoantennas in the world of single-molecule biology.
authors.affiliation: ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain.|Laboratory of Biophysics, Wageningen University , 6703 HA Wageningen, The Netherlands.
authors.forename: Emilie
authors.initials: E
authors.lastname: Wientjes
authors.affiliation: ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain.|Max Planck Institute for the Science of Light , D-91058 Erlangen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Renger
authors.affiliation: Glasgow Biomedical Research Building, Institute of Biomedical and Life Sciences, University of Glasgow , Glasgow G12 8QQ, U.K.
authors.forename: Richard
authors.initials: R
authors.lastname: Cogdell
authors.affiliation: ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain.|ICREA - Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona, Spain.
authors.forename: Niek F
authors.initials: NF
authors.lastname: van Hulst