A laboratory demonstration of the three-dimensional nature of in-line holography

Abstract

An experiment is described in which two semi-transparent reticles and a photographic plate separated by several centimeters are illuminated by a monochromatic point source in a typical in-line configuration. The resulting shadowgram is a hologram that contains information from both reticles. Illuminating this complex hologram with a similar point source with the reticles removed produces reconstructed real images at two separate locations whose coordinates are predicted from simple theory, and also produces virtual images of the reticles at their original coordinates. This experimentally confirms the three-dimensional capability of an in-line hologram. As imaging devices such as charge-coupled device sensors become cheaper and of higher resolution, a simple demonstration of this aspect of holograms, which can be projected to an audience, can be observed by sliding the image sensor along the axis. © 1999 American Association of Physics Teachers.