Performance of zoom homogenizer to control the size of illumination field.

We performed an illumination simulation, wave-optical simulation, and experiment on a zoom homogenizer and conventional beam homogenizer. The wave-optical simulation was performed for each lenslet using the shifted angular spectrum method for effective memory use. In the experiment, the parameters of the zoom homogenizer and beam homogenizer at all zoom positions were set using a system matrix. The uniformity and peak effect of the beam homogenizer were 16.57% and 16.63%, respectively, but those of the zoom homogenizer were 7.15% and 1.46%, respectively. The illumination field generated by the zoom homogenizer had a higher uniformity and lower peak effect at all zoom positions than the conventional one.