DIFFRACTIVE PHASE ELEMENTS THAT SYNTHESIZE COLOR PSEUDO-NONDIFFRACTING BEAMS

The design of diffractive phase elements (DPE's) for generating color pseudo-nondiffracting beams (PNDB's) in a multiple-wave illuminating s ystem by the conjugate-gradient method is described. The axial-intensi ty distributions for dual-color PNDB's generated by the DPE's are show n. The color PNDB's behave as segmented axial-intensity distributions; in each of segments only one color persists. The sequence of waveleng th components in the color PNDB's can be arbitrarily preset. Three-dim ensional plots of a dual-color PNDB indicate the characteristics of a beam with high transverse resolution. (C) 1998 Optical Society of Amer ica.