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The design of a diffractive phase element (DPE) that simultaneously implements wavelength demultiplexing and focusing is carried out on the basis of the general theory of amplitude-phase retrieval. The designed DPE is fabricated with optical contact lithography. Three masks are needed to produce the surface-relief structure of the DPE with eight quantized levels in depths. Experiments demonstrate that the designed DPE can successfully implement both the functions of demultiplexing three different-wavelength beams and focusing each component at a predesignated position simultaneously. Experimental measurements are in good agreement with the results of numerical simulations.

A coherent optical system composed of a holographic mask and two Fourier lenses is described for performing an arbitrary linear transform. A set of equations for determining the amplitude-phase distribution of the mask is given. As a specific transform, the Walsh-Hadamard transform for orders 32 and 64 is optically made in 1-D space.

By combining a large holographic optical lens or a Fresnel lens with a photoresist plate, a density color coding system for a large format picture is proposed and experimentally demonstrated. Based on partial coherence theory, a rigorous theoretical analysis is given and confirmed by the experimental results.