Multifocus dichromated gelatin hololens.

A method of making dichromated gelatin holographic lenses (hololens) with many equal intensity foci and some applications of the lens are described. The method employs a specially designed contact screen in a coherent optical spatial filtering system with the resulting holographic lens recorded in a dichromated gelatin film. The principle of the design and a detailed discussion of the various space–bandwidth products of the optical system are discussed. For demonstration, a 25-focus holographic lens has been made. As examples of the application of the multifocus hololens, the experimental results of its usages in the reproduction of 25 replicas of an image and in a real-time Vander Lugt matched filter pattern recognition system are presented.