1. A system comprising: an illumination source arranged to produce electromagnetic radiation having a coherence length of less than 30 microns; a reference optical element; a phase controlled interferometer arranged to: receive the radiation from the illumination source; split the radiation between a target and the reference optical element, wherein the interferometer is arranged to controllably introduce a phase between radiation directed to the target and to the reference optical element, and, generate, from reflected radiation from the target and from the reference optical element, an interference beam; an imaging unit arranged to receive the interference beam and generate a plurality of interferometry images corresponding to different introduced phases at at least one of a pupil plane and a field plane, and an analysis unit arranged to derive from the interferometry images at least one target characteristic.