Width of the apodization area in the case of diffractive optical elements with variable efficiency

We present simulations of averaged intensity of light behind apodized phase masks. Two types of apodization profile were assumed: Gaussian and tanh. In reality, because of limitations of electron-beam exposure system used for phase mask fabrication, we simulated phase masks with eight values of step height. For comparison, the averaged intensity distributions behind ideal phase masks with variable intensity were also calculated. Simulations and description of intensity distribution perturbations due to phase jumps in real apodized phase masks were performed.