A beam homogenizer for digital micromirror device lithography system based on random freeform microlenses

Abstract We report a novel beam homogenizer for digital micromirror device lithography system. Such a beam homogenizer contains only one random freeform microlens array (rfMLA). And the rfMLA consists of different freeform microlenses. By the individual design and irregular arrangement of the microlenses, efficient and uniform beam shaping results have been obtained, and the interference patterns in particular are greatly weakened. Compared with traditional beam homogenizer, the energy efficiency has been increased from 62.00% to 69.70%, and the uniformity for incoherent light and coherent light have been improved from 91.93% to 97.60% and from 79.00% to 94.33%, respectively. rfMLA has great potential for enhancing the performance of DMD lithography system and other optical systems, particularly for the homogenization of the beam and the integration of the system.