How does holography create a three-dimensional image of an object?

Holography creates a three-dimensional image by recording both the amplitude and the phase of light waves reflected from an object, whereas ordinary photography captures only intensity.123

To achieve this, a coherent light source, typically a laser, is split into two beams. One beam (the object beam) reflects off the subject, while the other (the reference beam) is directed onto a recording medium, such as a photographic plate. When these two beams meet on the plate, they interfere with one another, creating a complex pattern of interference fringes that encodes the object's depth and height information.234

The resulting hologram appears as an unrecognizable pattern of stripes and whorls. However, when this record is illuminated with coherent light, the fringes act as a diffraction grating, bending the light to reconstruct the original wave fronts. This process recreates the light field of the original object, allowing the viewer to perceive the image with three-dimensional characteristics, including parallax.243