Sharpening emitter localization in front of a tuned mirror

Single-molecule localization microscopy(SMLM)aims for maximized precision and a high signal-to-noise ratio1.Both features can be provided by placing the emitter in front of a metal-dielectric nanocoating that acts as a tuned mirror2–4.Here,we demonstrate that a higher photon yield at a lower background on biocompatible metal-dielectric nanocoatings substantially improves SMLM performance and increases the localization precision by up to a factor of two.The resolution improvement relies solely on easy-to-fabricate nanocoatings on standard glass coverslips and is spectrally and spatially tunable by the layer design and wavelength,as experimentally demonstrated for dual-color SMLM in cells.