Diffraction efficiency of binary optical elements

Abstract

We examine the role of processing errors on diffraction efficiency of binary optical elements and the validity of the Fourier model to predict diffraction efficiency. We show that mask alignment error can significantly degrade efficiency. Models based on the Fourier theory can adequately predict both the magnitude of diffraction efficiency and its sensitivity to processing errors for optically slow elements (f/b). For optically fast elements (<f/2), a rigorous model is required for good predictive accuracy. We use our model to indicate the sensitivity of diffraction efficiency to processing errors.