Near-field designs of Fresnel and Gabor zone plates are computationally analyzed by using versions that allow the foci to be brought closer to the plate than in the usual far-field applications. It is found that the Fresnel plate has a dominant primary conjugate pair of foci well inside the far-field region and a more intense primary focus and smaller off-focal-plane sidelobes than the near-field Gabor systems, thus yielding a superior imaging performance.
© 2000 Optical Society of America
(080.2740) Geometric optics : Geometric optical design
(080.3620) Geometric optics : Lens system design
(260.1960) Physical optics : Diffraction theory
(350.4010) Other areas of optics : Microwaves
T. D. Beynon and R. M. R. Strange, "Computational study of diffraction patterns for near-field Fresnel and Gabor zone plates," J. Opt. Soc. Am. A 17, 101-106 (2000)