hologram

hologram \hol"o*gram\, n. A photographic image giving the observer a seemingly three-dimensional view of the represented object. The three-dimensional effect is produced by exposing a photographic recording medium to an interference pattern generated by a coherent beam of light (as from a laser) reflected from the subject, interacting with a beam directly from the source. The full three-dimensional effect requires illumination of the image with coherent light, but less perfect three-dimensional visual effects may also be observed when the hologram is illuminated with white light. [PJC]