Computational method for testing computer‐generated holograms

Abstract

A procedure based entirely on computer simulation is developed for testing the quality of computer-generated holographic optical elements (CGHOEs). This new testing method may be of help in optimization techniques in the future. We introduce a mathematical quantity, the correlation, to characterize the performance of the studied CGHOE. Our procedure examines how the correlation between the object and the reconstructed image depends on various parameters of the CGHOE, such as the reference amplitude, the location and number of the object points, the number of gray levels used, and the pixel size on the hologram. To reduce computer running time, we introduce a new method for modeling the reconstruction of a computer-generated hologram (CGH): instead of using the whole information stored on the CGH, we use randomly chosen pixels (square-shaped slits) of the CGH. In this way, computer running time becomes smaller by two orders. A postquantization procedure is developed that, under certain conditions, improves the quality of the CGHOE. Our model uses amplitude holograms and 2-D objects, but in principle, there are no difficulties in extending it to phase holograms and 3-D objects.