High-coherence light beam illumination homogenization based on phase perturbation and statistical averaging

When fly’s eye lenses are applied in the beam homogenization of high-coherence lasers, the interference induced by sub-beams leads to the formation of comb-like patterns that significantly reduce the illumination uniformity. We carried out a theoretical and experimental study of an optimized fly’s eye lens system for high-coherence laser illumination homogenization. An improved method is applied to enhance the phase perturbation, and the adverse interference effects are ultimately mitigated by statistical averaging. A nonuniformity of less than 5% was achieved within a 1.6 mm×1.6 mm square illumination area by optimizing parameters such as illumination defocus distance, diffuser grit, rotation speed, and exposure time.