hologramas

Hologramas, or holograms, are three-dimensional images created by recording and reconstructing the light field that comes from an object. Unlike conventional photographs, a hologram stores phase information in addition to intensity, allowing a viewer to perceive depth and parallax when the hologram is illuminated by a suitable light source, typically a laser or another coherent beam.

Holography involves splitting a coherent light beam into an object beam that interacts with the subject and a reference beam that does not. The two beams interfere on a recording medium, creating an interference pattern that encodes the light’s amplitude and phase. Reconstruction uses a light source similar to the original reference beam to reconstruct the light field.

Holograms can be classified by geometry and illumination. Transmission holograms are viewed with light passing through the media, while reflection holograms are seen from the same side as the light source. In-line holograms align object and reference beams. Digital holography records interference digitally and computes reconstructions with a computer.

Applications range from security holograms on banknotes and identity documents to artistic installations and product packaging. Holography is used in microscopy and metrology, and as the basis for holographic displays and augmented-reality systems. It has also been explored for data storage and non-destructive testing.

The concept was introduced by Dennis Gabor in 1947, who described a method to record the wavefront of light. Realistic holograms became practical in the 1960s with laser technology, and later developments by researchers such as Leith and Upatnieks expanded white-light and digital holography. The field remains active in research and industry.