The invention relates to a device (100) for processing light radiation (108), comprising at least two reflective optical elements (102, 104) which define a multi-pass cavity (106) such that at least one of said optical elements (102, 104) reflects said light radiation (108) at least twice in at least two different reflection locations. The device is characterized in that it comprises at least one element, referred to as a correction element, having at least one location, referred to as a correction location, which produces a reflection or transmission of said optical radiation and of which the surface is irregular such that the spatial-phase profile of said correction location (116) has a different phase shift for a plurality of different reflection or transmission points at said correction location (116). The invention also relates to a method and to a system for designing such a device (100).