We employ the conjugate-gradient method to design diffractive phase elements (DPE’s) that implement the predefined axial-intensity modulation over a given axial region. We introduce an error function for guiding the design of DPE’s and for evaluating their performance. Numerical simulations are carried out for several examples, for instance, the design of the DPE that generates four foci with equal or unequal spacing between the consecutive foci along the optical axis and the DPE that produces a sinusoidlike axial-intensity modulation. The obtained results show that the designed DPE’s can satisfactorily match practical requirements.
© 1998 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
Rong Liu, Ben-Yuan Gu, Bi-Zhen Dong, and Guo-Zhen Yang, "Design of diffractive phase elements that realize axial-intensity modulation based on the conjugate-gradient method," J. Opt. Soc. Am. A 15, 689-694 (1998)