Axial coding in full-field microscopy using three-dimensional structured illumination implemented with no moving parts.

We report a simple optical setup to produce both axial and lateral structured illumination through a single objective lens. With a minimum of six full-field images obtained without moving either the sample or the microscope objective, 100 nm diameter fluorescent beads can be localized axially with an accuracy of 50 nm in a 1.76-microm-thick layer. We show that this axial localization improvement can easily be combined with classical lateral structured illumination, so that lateral resolution enhancement by a factor of 2 is maintained.