Sharpening emitter localization in front of a tuned mirror

Single-molecule localization microscopy (SMLM) aims for maximized precision and a high signal-to-noise ratio(1). Both features can be provided by placing the emitter in front of a metal-dielectric nanocoating that acts as a tuned mirror(2–4.) 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.