A method and apparatus for elimination of speckle pattern in optical system by reducing coherence. The invention is based on the use of a rotating microlens array having a rotational speed chosen with reference to laser parameter. For a continuous laser this relationship consists in that the exposure time is sufficient for overlapping at least 10.sup.4 spot sizes of the speckle. For a pulse laser, the laser pulse time should be sufficient for shifting the speckle spot at least by the magnitude of its diameter. Several embodiments with modified coherence reduction units are available. One modified embodiment describes a rotating inclined plate which enhances coherence reduction by scanning the over the surface of the diffuser. Another embodiment describes the use of an optical conical rod with total internal reflection for creation of a plurality of non-coherent light sources.
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