Optical interference device

A method for producing a spatially distributed interference light pattern, comprising

• receiving a collimated beam of light;
• directing the collimated beam of light to a phase shifter array comprising a plurality of blank cells, wherein:
• the blank cells do not impose different phase shifts in the collimated beam of light incident on the blank cells;
• and
• the blank cells are distributed throughout the phase shifter array, thereby forming a structure that divides the phase shifter array into a plurality of array sections, wherein each array section in the plurality of array sections is different from the blank cells, and comprises an array of cells for producing optical light channels from respective rays of the collimated beam of light, at least some of the optical light channels having different phase shifts as the collimated beam of light transmitted through the phase shifter array;
• providing a focusing element having a focal distance;
• producing, by the focusing element, from the optical light channels, a focused beam of light in its focal plane and an image downstream for detection by an optical detector;
• providing an optical spatial filter at the focal distance of the focusing element and filtering the focused beam of light by the optical spatial filter to produce the spatially distributed interference light pattern in zeroth order for detection by the optical detector;
• and
• measuring spatial intensity distribution of the collimated beam of light.