Dennis Gabor and the Hologram Theory

When questioned about the future, we often respond with painted Hollywood-influenced concepts and inventions. However, we have yet to truly understand the impact of thought and how often these made-up scenarios influence young scientists and engineers worldwide. One truly futuristic concept of the past that has yet to develop into a mainstream household commodity is the hologram. Having been first proposed in 1947 by Dennis Gabor, a Hungarian electrical engineer and physicist, the hologram continues to perplex modern technology companies with its physical makeup and complex function. Gabor invented the method of storing on photographic film three-dimensional (3-D) images of the information pattern encoded on a beam of light. He later became the recipient of the 1971 Nobel Prize in Physics for his outstanding Hologram Theory and the development of holograms.

The term hologram derives from the combination of the Greek words holos, meaning whole, and gramma, meaning anything written. In essence, a hologram or electromagnetic energy hologram is defined as the whole, holos, 3-D message contained or written in a single beam of light, gramma – this compares to the partial message that’s contained in a two-dimensional (2-D) photograph and is the major feat which distinguishes 2-D imaging from 3-D. However, technology wasn’t yet able to produce such mechanisms when Gabor first came up with his Hologram Theory in 1948 and it wasn’t until the invention of the laser in 1960 that experiments with this theory were able to commence.

Processes within holography share similarity to those within photography however there are major differing factors. As a whole, holography is a two-stage process. The first stage consists of recording a hologram in the form of an interference pattern or pattern showing the interaction of waves that are coherent with one another due to the two waves functioning at the same frequency. This feat is similar to the iridescent pattern or the mixing of colors that is visible to the naked eye in floating soap bubbles or atop an oil film. The second stage of holography requires the hologram to act as a diffraction grating or medium that splits, or diffracts, light into multiple beams that travel in different directions while the image of the subject is then reconstructed in order to display the final holographic image; the diffraction process gives each beam the ability to reconstruct the entire object. During this process, both intensity as well as the phase of a light wave are being recorded thus producing a 3-D picture of an object that can be viewed from several angles. An example of a modern technology that repeatedly exercises the benefits of holography lies within the medical field and is termed x-radiation or the x-ray.

Meanwhile, conventional photography uses a process that is much more simplified. Unlike holography, light intensity is the only medium that is recorded thus leading a photographing device to produce 2-D figures of an object rather than the aforementioned 3-D. This is also why figures within photographs can only be viewed from one angle at a time rather than showing a full 360-degree image.
Both of these image producing mediums, photography and holography, are light dependent methods of storing information. This means that both methods record information contained in the visible light region, the optical region, of the electromagnetic radiation spectrum and that lasers are imperative in the advanced processes of these functions. As a medium itself, the laser is an indispensable coherent light source that makes both conventional photography and optical holography possible.

An interesting fact about the hologram is that the general concept plays into the famous Holographic Principle which was first introduced by the Dutch theoretical physicist Gerardus’t Hooft and Leonard Susskind circa the 1980s. This principle states that 3-D spaces can be mathematically reduced to 2-D projections and that the 3-D universe we continuously experience and perceive is merely the “image” of a 2-D one. Many physicists strongly believe that the universe is simply one giant hologram. Even though we have come to see the importance in certain mediums that use holography, such as x-rays, we still question the importance of individual holograms. As unfamiliar with the concept as many consumers may be, this sub-field of laser technology may slowly start to find its place within our everyday lives as device-based learning begins to flourish.

With smartphone technology developing at such a rapid pace, it’s safe to assume that these hand-held devices may begin to experience changes within their hardware systems. Samsung has since advertised a smartphone prototype which displays holographic images “mid-air” via the cell-phone screen.

Young scientists and engineers worldwide are becoming more and more interested with holograms and all that is certain is the fact that major changes with this specific use of technology are currently underway and may even come to stare us in the face within the next five to ten years.