Simulating temporal speckle with prescribed correlation properties in optical lithography.

We describe a method of simulating temporal speckle often encountered in optical lithography. The first step of the method is to generate numerically optical fields with prescribed temporal coherence properties using a shot noise process. By properly arranging the data for instantaneous intensities calculated from the generated fields, one can construct virtually temporal speckle patterns that satisfy all the necessary conditions. As some illustrative examples, we examine the variation of the temporal speckle contrast as a function of the exposure time of the detector by means of these speckle patterns. Our method would provide an intuitive understanding of hardly observable temporal speckle and serve as an educational tool for students and professionals in optics.