The marked chromatic aberration of a Fresnel-zone-plate lens can be used as a variable narrow-band optical filter, and thus a holographic spectrometer. The filtering properties of the zone plate are analyzed, with particular emphasis on the effect of a central stop over the low-order rings. It is shown that the central stop can markedly improve the rejection of frequencies outside the pass band without significant degradation of the spectrometer resolution.
P. N. KEATING, R. K. MUELLER, and T. SAWATARI, "Fresnel-Zone-Plate Spectrometer with Central Stop," J. Opt. Soc. Am. 62, 945-948 (1972)