SOLUTION TO FRESNEL ZONE PLATE PROBLEM

The diffraction problem for the Fresnel half-period zone plate is solved. The zone plate behaves as a lens with marked chromatism which can be taken advantage of for use in a spectrometer. The multiplicity of foci associated with the zone plate are examined in detail, and it is shown that the spectral range that can be focused without overlap is 3?min=?max. The wavelength resolution is X/AX (m+l)/0.445, where m is the number of transparent half-period zones. For m = 300, this corresponds to a f-wave number resolution at 20 microns. The intensity at the focus is given approximately by 47(to+1)2, where I is the intensity at the zone plate. The transmitted power that falls within the airy disk is proportional to the area of the zone plate. © 1969, American Association of Physics Teachers. All rights reserved.