Two new methods of improving optical image quality

Two simple methods are presented by which the coherence between a laser light source and an illuminated object can be destroyed in optical systems where this coherence is undesirable. Both methods employ rotating phase changing disks; the first introduces a random time varying phase relationship across the area illuminated in the object plane, whereas the second produces a rapid, regular phase variation across this area. Results are claimed to be comparable to those obtained using normal incoherent light.