Computer-generated holography as a generic display technology

Invented in 1947 by Dennis Gabor, holography-from the Greek holos, for whole-is a 3D display technique that involves using interference and diffraction to record and reconstruct optical wavefronts. Holography's unique ability to generate accurately both the amplitude and phase of light waves enables applications beyond those limited by the light manipulation capabilities of lens- or mirror-based systems. Computer-generated holography avoids the interferometric recording step in conventional hologram formation. Instead, a computer calculates a holographic fringe pattern that it then uses to set the optical properties of a spatial light modulator, such as a liquid crystal microdisplay. The SLM then diffracts the readout light wave, in a manner similar to a standard hologram, to yield the desired optical wavefront. Although CGH-based display systems can be built today, their high cost makes them impractical for many applications. However, as compute power and optical hardware costs decrease, CGH displays will become a viable alternative in the near future.