PSFcheck ring pattern at various SNR

<p>The imaged PSFcheck pattern consists of a nanometric set of ring-like laser-written structures with a separation of 10 &micro;m between each. The mean FWHM of these patterns was calculated to be 208 nm. A NanoImager-S microscope (ONI, Oxford Nanoimaging), equipped with a 100X 1.4 NA, oil-immersion objective (Olympus) was used to image the PSFcheck patterns in widefield fluorescence mode. Sample excitation was provided by a 561 nm laser and emission was collected with a 575-616.5 emission filter. A sCMOS sensor (Hamamatsu, Orca-0Flash4.0 V3) was used for image aquisition at 30 fps and 117 nm pixel size.&nbsp;</p>