A light source includes a plurality of ultraviolet (UV) light emitting diodes (LEDs) and an LED phase shift controller coupled to the plurality of UV LEDs adapted to control the phase shift of each UV LED in the plurality of UV LEDs. The plurality of UV LEDs forms a UV LED array. An ultraviolet lithography system can include a light source as described above. The system can further include a mirror assembly in a light path of the light source, the mirror assembly having a polarization mirror with an interference coating. A method provides a light source for an ultraviolet lithography system including the element of providing an plurality of UV LEDs that emit UV light and the element of controlling a phase shift of the plurality of UV LEDs with an LED phase shift controller coupled to each UV LED or arrays of the UV LEDs in the plurality of UV LEDs.