Angle-dependent encoding of multiple asymmetric symbols in a binary phase hologram with a spatial segmentation

A method of encoding multiple asymmetric symbols into a single thin binary Fourier hologram is presented. It assumes a combination of a spatial segmentation and carrier frequencies in order to achieve multiple reconstructed images selectable by the angle of the incident laser beam. The proper segmentation function with an optimized period allows us to encode a number of different objects with little loss of reconstruction quality. A special sequence of phase encoding steps and a binarization enable recording of asymmetric symbols into a binary hologram. The description of the design procedure is given, followed by the experimental results confirming the conclusions conceived from numerical simulations. The method can be used practically for the design of simple translucent holographic head-up displays.