Figure 3

Fluorescent nanopatterns for super-resolution microscope calibration. (a–c) Wide field fluorescence microscopy images of the collection of patterns written for assessing microscope performance, including (a) lines with from top to bottom decreasing line spacing under different orientation, a checkerboard pattern with in two dimensions decreasing line spacing, interdigitated lines with equal spacing, (b) interdigitated lines with from left to right decreasing spacing, a solid square with protruding small lines, a double helix, and (c) a nanoscale version of M.C. Escher’s Sky and Water I. Pattern positions on the microscope slide were recognized by sequences of larger arrays of solid fluorescent squares (not shown). (d–f) Structured illumination microscopy images of the patterns in (a–c). The improvement in resolution is apparent from the various line patterns and the protruding lines in the small square, but also known reconstruction artefacts like enhanced noise appear for instance around the double helix structure. Red arrows point to small defects in the fluorescent patterns. Scale bars are 2 µm.