Application of spatial-frequency spectrum method on diffractive optical element for beam smoothing

Diffractive optical element (DOE) is a promising technique to realize beam smoothing. To calculate the true performance of the DOE for beam smoothing, the spatial-frequency spectrum method has been used to re-define the performance parameters of the DOE for beam smoothing. In this paper, the spatial-frequency spectrum method is used to basically determine the performance limitation of the DOE for beam smoothing. Considering the low-pass filtering effect will be induced by physical process in the practical applications, the DOE is designed with the low-pass filtering effect in the optimization. Furthermore, the performance realized by utilizing the DOE and the time average technique is theoretically analyzed with the spatial frequency spectrum method.