Fig. 5.

(a-f) Confocal and STED pairs of images from HeLa cell samples where secretory vesicles have been tagged with Oregon Green 488. A gated STED system from Leica was used on this experiment. STED images have been acquired setting the depletion laser power to 20%, b), 60%, d) and 100%, f). The images are acquired using photon counting settings, and the confocal (a,c, and e) and STED (b, d and f) images are shown using the same color scale to minimize display effects. (g) Azimuth average of the FT of the confocal and STED images in c) and d). Green markers show the data from the STED images, and orange from the confocal ones. Corresponding fits of the data using the method described are also shown in the plots, dotted line for STED and solid for confocal. (h) AASCS obtained using different excitation powers in the STED laser on the same sample. The data have been calculated using the images a-f), amongst others. The AASCS is maximum for values of the depletion laser power of around 60%.