A method of performing 3D photoactivation microscope imaging includes providing a sample having a plurality of probes, each of the plurality of probes including a photo-activatable material. Probes from the plurality of probes are activated to form a sparse subset of probes, the sparse subset of probes having probes that are spatially separated by at least a microscope resolution. The sample is illuminated with a readout light source, and light emitted from activated probes is detected. Based on the light emission detected from the activated probes, localized three-dimensional positions of the activated probes are obtained.