Wave front sensor based on fourier filtering

A wave front sensor system, comprising:

• a first lenslet array comprising a plurality of lenses positioned to receive at least a portion of an incoming wave front;
• a mask positioned at a focal plane of the first lenslet array to receive and filter a Fourier transformed wave front that is produced by the first lenslet array at the focal plane, the mask including a plurality of sections, wherein each section of the mask is configured to receive light from a corresponding lens of the first lenslet array, each section of the mask configured to (a) produce a reference wave front from the Fourier transformed wave front incident thereon and (b) allow a portion of the Fourier transformed wave front incident thereon to pass therethrough, or reflect therefrom;
• and
• a sensor array comprising a plurality of light sensitive detectors and positioned to receive the reference wave front produced in (a) and the wave front in (b), and to detect an intensity value representative of a phase of the incoming wave front.