Binary, Multilevel, and Hybrid Holographic Optical Array Illuminators

Since the recognition of the importance of optical array illuminators [1] in the realization of parallel digital optical processors, a wide variety of optical components have been designed and demonstrated that convert a single laser beam into a regularly-spaced array of M × N equal-intensity light spots. Space-variant array illuminators, which form the spot array in a Fresnel plane or an image plane of the aperture are in general easy to design and fabricate, but they require uniform plane-wave illumination that is difficult to provide. Space-invariant array illuminators generate the spot array in the Fourier plane and are therefore rather immune to the exact shape of the incident beam, but they are more difficult to design and require tight fabrication tolerances.