Interference Imaging

Holography is "lensless photography" in which an image is captured not as an image focused on film, but as an interference pattern at the film.

The Transmission Hologram

The coherent light from the laser is split to form an object beam and a reference beam. The light from the illuminated object and the reference beam form an interference pattern on the film. This pattern (hologram) contains the information about the object which can then be viewed as a three dimensional image.

Viewing a Transmission Hologram

Holography is lensless photography. The image is captured in the interference pattern on the film, and the image can be reconstructed for viewing by shining the coherent light of a laser on the hologram. The eye is focused behind the film to see the image suspended in space. It shows the unique characteristics of holographic images.

The diverged laser beam should be placed in the same orientation with respect to the film as the reference beam which was used to make the hologram. Then the image will be seen in the same position as the original object with respect to the film. It is as if the light from the object was frozen in the film, and then continues to your eye when reconstructed with the laser light.