Wavefront sensor and method of using it

A method for use in optical detection, the method comprising:

• collecting input optical radiation though an encoder at a collection plane and applying to the collected input optical radiation a periodic modulation configured of a plurality of similar unit cells, each having a predetermined modulation function expanding at least a portion of the optical radiation impinging on the unit cell to a downstream predetermined proximity region, wherein the predetermined proximity region comprises one ore more sub-array unit cells associated with neighboring unit cells of the encoder;
• providing an array of sensor cells at a selected distance from said collection plane, said array of sensor cells is configured with cell geometry and arrangement providing a plurality of sub-array unit cells each comprising a predetermined number M of sensor cells and corresponding with unit cell of the encoder while being configured for collection of light components associated with one or more of said predetermined number of neighboring unit cells determined in accordance with said proximity region, and generating intensity map associated with output of said array of sensor cells in response to collected optical radiation;
• processing said intensity map in accordance with data about said predetermined modulation function for determining a mutual coherence function of the collection light.