Partial Coherent Simulation of Homogenization Systems using Micro Lens Arrays

Systems for homogenization of partial coherent light sources, as for example, Excimer lasers and LED’s are widely used. Homogenization can be done using diffractive optical elements or micro lens array. Especially micro lens arrays are used for a long time and several concepts for setup and optimization of components are published. An exact prediction of the optical quality can help to save time and money and requires an accurate modeling of the incident light distribution and simulation of light propagation through the system. The authors show that the modeling of the light distribution must include the spatial and temporal coherence and the simulation of light propagation must contain diffraction and interference effects that can be caused for example by apertures of the micro lenses in the lens array. The modeling of partial coherent light and light propagation is explained and the concepts are demonstrated on an example for the homogenization of an Excimer laser beam.