R. Liu et al., GENERATION OF PSEUDO-NONDIFFRACTING BEAMS WITH USE OF DIFFRACTIVE PHASE ELEMENTS DESIGNED BY THE CONJUGATE-GRADIENT METHOD, Journal of the Optical Society of America. A, Optics, image science,and vision., 15(1), 1998, pp. 144-151
The design of diffractive phase elements (DPE's) for generating pseudo
-nondiffracting beams (PNDB's) is carried out by employing the conjuga
te-gradient method. By selecting a trapezoid profile as the preset axi
al intensity distribution ta guide the design and by using an error fu
nction with a weighting factor to evaluate the performance of the DPE,
we develop a model design and obtain a satisfactory diffractive patte
rn of a single-segment PNDB. We demonstrate the effectiveness of the c
onjugate-gradient. method in the design of DPE's that produce multiple
-segment PNDB's in which two consecutive segments are separated by a d
ark region along the optical axis. We also evaluate the degree of nonu
niformity of the axial intensity over a given axial region. The design
results match the requirements quite well. (C) 1998 Optical Society o
f America.