Theoretical and Experimental Investigation of Plane Wave Diffraction from an Amplitude Modified Fresnel Zone Plate

A new class of gratings is produced by combining the radial grating (rg) with the fresnel zone plate (fzp). besides having an azimuthal periodicity, these gratings focus the incident beam at a specific distance. this paper investigated the diffraction from modified fresnel zone gratings (mfzgs) theoretically and experimentally. our approach was to solve the fresnel-kirchhoff integral in the cylindrical coordinate system for a plane beam on an mfzg. the experimental results of diffraction patterns of a laser beam from the amplitude type of mfzgs confirmed the theoretical predictions well. the near-field diffraction patterns agreed with the patterns obtained from theoretical calculations.