Holography
Advanced
Records interference patterns to reproduce 3D images.
A hologram records both the amplitude and phase of light through interference with a reference beam; illuminating it reconstructs a 3D image.
Security holograms on bank cards.
Needs coherent light for recording.
In more detail
Holography records the interference pattern between a reference beam and light scattered from an object. Illuminating the recorded pattern reconstructs a three-dimensional image.
Real-world uses
- Holograms appear on credit cards for security.
- Holographic displays and data storage are under development.
- Holograms on credit cards and museum exhibits store interference patterns that reconstruct a three-dimensional image.
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Frequently asked questions
Why does a hologram look 3D?
It reconstructs the wavefront of the original object, which preserves depth information.
Does a hologram need a laser to view?
Some do, but many can be viewed in white light.
Why does a hologram look three-dimensional?
It records the full wavefront, including the phase, so the viewer sees the same light as from the original object.
Related topics in Optics
Birefringence · Optical activity · Coherence and lasers · Fermat's principle · Fresnel and Fraunhofer diffraction · Fibre optics numerical aperture