Apparatus for beam homogenization and speckle reduction

摘要

This invention greatly improves the quality of images obtained using optical systems illuminated by coherent light. It does so by removing the undesirable psuedo-random variations in the final image due to interference speckle and inhomogeneities in the spatial intensity distribution of the light source. A bundle of light-guiding fibers is interposed between the illumination source and the imaging system. Non-uniform propagation within the fiber bundle creates a psuedo-random phase variation across the illumination beam, which gives rise to a dynamic interference speckle pattern superimposed upon the desired image acquired by the optical system. Rotating the fiber bundle around the axis of propagation, whilst simultaneously integrating the output of the photosensitive detector over a period of time, substantially removes variations due to source inhomogeneities and coherent interference.