Abstract

A model describing the image irradiance of two images produced by a multiple grating reflection type focusing element is developed. The gratings may be formed simultaneously or sequentially, and the recording medium can change thickness during processing. In the algorithm, the spot size and location of the image are first calculated by ray tracing from each surface grating in the multiplexed grating element. The efficiencies of these rays are then computed with a multiple grating model which allows for coupling between the fields in the grating volume. Finally, the efficiency of each ray is weighted by a factor corresponding to the intensity profile of the reconstruction beam. The sum of these weighted rays per unit area in the image plane determines the relative image irradiance. A comparison is then made between the image irradiance produced by experimental multiple focused elements and the calculated irradiance pattern. The model predicts the relative profile and the size of the irradiance patterns.

© 1986 Optical Society of America