Fig. 6: Effect of the emitter-to-mica substrate distance on the axial position localization.

a A schematic illustration of the experimental configurations. The sample configurations were identical to those in Fig. 5c. b Representative Z-axis position-dependent images of the fluorescent nanospheres deposited on both surfaces captured at ten different X positions. The fluorescence images obtained for the nanospheres deposited on the glass and mica surfaces are indicated by yellow and cyan arrowheads. c Localized Z-axis positions of the fluorescence nanospheres deposited on the glass substrate at pre-defined focal positions of the microscope objective determined at ten different X-positions. The solid lines show linear fits. The data are plotted with an offset for clarity. Two sets of samples were prepared and tested to ensure data reproducibility.