A statistically sparse subset of switchable optical sources in a sample is activated, and the activated switchable optical sources are excited such that optical beams are emitted from the activated switchable optical sources along at least two optical paths. A first wavefront modification in a first optical beam emitted from the activated switchable optical sources along a first optical path is introduced and a second wavefront modification in a second optical beam emitted from the activated switchable optical sources along a second optical path is introduced, the second wavefront modification being distinct from the first wavefront modification. The first and second optical beams are interfered with each other to produce a plurality of output beams, and three-dimensional position information of the optical sources is determined based on an intensity of each output beam from the plurality of output beams.