A fluctuation-insensitive diffractive optical homogenizer for excimer beam-shaping

The problem of designing a diffractive optical homogenizer that produces an annular uniform intensity beam from a spatially variable and partial-coherent source such as excimer is considered. A modified target pattern which corresponds to full-coherent field is presented to ensure the homogenizer can work well in partial-coherent field generated by excimer. Because modified target pattern is proportional to the deconvoluation between ideal target pattern and slit function, to avoid the mathematical puzzle of deconvolution, an artificial modification on target pattern is proposed and good numerical results are produced. After dividing the homogenizer into several sub-elements with proper numbers, we find it is quite insensitive to the amplitude fluctuation of input field. With our method, the homogenizer is possible to be used in partial-coherent and fluctuant field.