Holography 921 The inventor

The word 'hologram' is derived from the Greek words holos and gramma, which translate as 'whole writing'.

Holography was invented in 1947 by the Hungarian scientist Dennis Gabor (1900-1979), while trying to develop a method of producing 'lensless' images to improve the poor resolving power of electron microscopes. Gabor was awarded the Nobel Prize in 1971 for his work on holography.

In Gabor's Nobel acceptance speech he explained the difference between photography and holography in the following terms: 'In an ordinary photographic image important information is missing. It reproduces the intensity of the light waves but tells us nothing about their phase. Phase depends on what direction the wave is coming from and how far it has travelled from the object which is being imaged. We lose the phase if there is nothing to compare it with! Let us see what happens if we add a standard to it, a coherent background'.

There are some practical difficulties associated with obtaining interference patterns for light from conventional sources, and high quality holograms were produced only after the invention of the laser in 1960.

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