Metastable Dark States Enable Ground State Depletion Microscopy of

pubs.acs.org/NanoLett

Metastable Dark States Enable Ground State Depletion Microscopy of Nitrogen Vacancy Centers in Diamond with DiffractionUnlimited Resolution Kyu Young Han,†,‡ Seong Keun Kim,‡,§ Christian Eggeling,*,† and Stefan W. Hell*,† †

Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Go¨ttingen, Germany and ‡ Department of Chemistry and § Department of Biophysics and Chemical Biology, Seoul National University, Seoul 151-747, Korea ABSTRACT Current far-field optical nanoscopy schemes overcome the diffraction barrier by ensuring that adjacent features assume different states upon detection. Ideally, the transition between these states can be repeated endlessly and, if performed optically, with low levels of light. Here we report such optical switching, realized by pairing the luminescent triplet and a long-lived dark state of diamond color centers, enabling their imaging with a resolution >10 times beyond the diffraction barrier (