Patent ID: 7586959

Claim:
An apparatus for reducing speckle, comprising: a first coherence-reducing component, comprising a first array of transparent first elements arranged to receive different, respective first portions of a light beam, the first elements having at least two different optical lengths with respect to the light beam passing therethrough and outputting the respective first portions as respective substantially collimated first sub-beams; a second coherence-reducing component, comprising a second array of transparent second elements arranged to receive different, respective second portions of each of the first sub-beams, the second elements having at least two different optical lengths with respect to the light beam passing therethrough and outputting the respective second portions as respective substantially collimated second sub-beams; and a light combiner arranged to combine the second substantially collimated sub-beams into a substantially collimated output beam, wherein one or both of the first and second coherence-reducing components further comprises a bypass so as to allow a portion of the light beam to bypass at least one of the first and second coherence-reducing components.