Definition of absorption hologram

DataRay Inc. - ISO 11146-Compliant Laser Beam Profilers

Photonics Dictionary

absorption hologram: An absorption hologram is a type of hologram in which the image is formed by variations in the absorption of light within the recording medium. Unlike traditional holograms that rely primarily on phase differences and interference patterns to create a three-dimensional image, absorption holograms use differences in the opacity of the medium to encode the holographic information.

Formation: Created when a recording medium absorbs light in certain regions more than others, resulting in a pattern of varying opacity that corresponds to the holographic image.

Recording medium: Typically involves a photosensitive material that changes its absorption properties when exposed to light. Common materials include certain types of photographic films and photopolymer materials.

Reconstruction: When illuminated with coherent light (such as laser light), the variations in absorption within the hologram diffract the light to reconstruct the original image. The reconstructed image can be viewed in three dimensions.

Applications: While less common than phase holograms, absorption holograms can be used in various applications, including security features, artistic displays, and scientific visualization.

Contrast and resolution: The quality of the holographic image depends on the contrast and resolution of the absorption pattern in the recording medium. High contrast and fine resolution lead to clearer and more detailed holographic images.

In summary, an absorption hologram encodes three-dimensional information through variations in the absorption properties of the recording medium, allowing the original scene to be reconstructed when illuminated appropriately.