BINARY GRATING WITH VARIABLE BAR SPACE RATIO FOLLOWING A GEOMETRICAL PROGRESSION

Apodizing the apertures of a binary grating with a variable opening ra tio, the diffraction produced by the pupil is eliminated from its spec trum. We study the behavior of a unidimensional binary grating whose b ar/space ratio is expressed as a geometrical progression. The experime ntal and simulation results of Fraunhofer diffraction patterns produce d by this type of grating are compared with the spectrum of a Ronchi t ype ruling showing the elimination of the diffraction pupil in one dim ension.