SPATIAL-FREQUENCY FILTERING IN HOLOGRAPHIC IMAGE-RECONSTRUCTION

We show that reconstructing a hologram by its object beam leads to spa tial filtering, namely, to the suppression of spatial frequency compon ents that are perpendicular to the plane of the recording beams. We co nduct experiments by rotating the transparencies of Ronchi gratings an d crossed gratings and measuring the corresponding diffraction efficie ncies. Good agreement is found with a theory based on image reconstruc tion with a beam that does not quite satisfy the Bragg condition.