The first to answer the question "What is a hologram?" the Hungarian physicist Denesh Gabor tried to answer in the late 40s. He was destined to become the founder of holography and at the same time the creator of the first hologram (he also invented this term), for which he subsequently received the Nobel Prize.
However, the quality of the first holograms was low due to the use of primitive gas-discharge lamps for their creation. Everything changed in the 60s with the invention of lasers, which contributed to the rapid development of holographic technology. The first high-quality laser holograms were obtained by the Soviet physicist Yu. N. Denisyuk in 1968, and 11 years later, his American colleague Lloyd Cross created an even more complex multiplex hologram.
Principle of hologram formation
Holography is a special photography technology that produces three-dimensional (volumetric) images of objects. This became possible due to two properties of light waves - diffraction (refraction, bending) and interference (redistribution of light intensity when several waves are superimposed).
In the process of visualization of a hologram at a certain point in space, two waves are added - the reference and the object, formed as a result of the separation of the laser beam. The reference wave is formed directly by the light source, and the object wave is reflected from the recorded object. There is also a photographic plate on which dark stripes are "imprinted" depending on the distribution of electromagnetic energy (interference) in a given place.
A similar process takes place on ordinary photographic film. However, to reproduce an image from it, a printout on photographic paper is required, while with a hologram, everything happens a little differently. In this case, to reproduce the "portrait" of the object, it is sufficient to "illuminate" the photographic plate with a wave close to the reference one, which converts it into a wave close to the object wave. As a result, we will see an almost accurate reflection of the object itself in the absence of it in space.
3D hologram and its application
A modern hologram is essentially a three-dimensional projection of a three-dimensional image of a specific object. 3D-hologram confidently masters the most various spheres of human activity. There are many examples of this. One of them is holograms in the air. These are holographic models (scale 1: 1) and 3D pyramids. At presentations, conferences, exhibitions and other events of various levels, spatial holograms are increasingly used, which are created using holographic projectors. The simplest 3D projector can be made with your own hands from an ordinary smartphone.
How holographic projectors work
Modern projector models are capable of creating a huge number of 3D effects. Among them are holographic video projections created through the use of reverse video projection transparencies. The video stream, passing through them, creates an image literally "floating" in the air.
Among the latest technologies for information transmission are videoconferencing and interactive holography, which creates the effect of a transparent surface hanging in the air.
The capabilities of holographic projectors are constantly expanding with the development of modern technologies, and the quality of images is improving. They are becoming more affordable and compact. Today, at parties and in nightclubs, you can find laser holographic mini-projectors that create complex laser "patterns" that are combined with smoke effects.
The first person in the form of a hologram was the heroine of "Star Wars" (Episode IV) Princess Leia. Since then - and more than 40 years have passed - holography has become firmly established on movie screens, along with other special effects in numerous Hollywood blockbusters.
The fact that since then holography has made a dizzying technological breakthrough became clear on May 19, 2014 in Las Vegas at the presentation of the Billboard Music Awards, when the late Michael Jackson sang and danced in front of shocked audiences, as in the good old days. The miraculous "resurrection" is made possible by the stunning hologram created by Pulse Evolution.
Holography on smartphone display
With the advent of mobile phones, and later smartphones, it became clear that one day the paths of these two iconic technologies of the 21st century will intersect. And so it happened. And now YouTube is overflowing with user advice on how to turn your smartphone into a holographic mini-projector.
The fresh idea was picked up by one of the leaders in the production of digital photo and video cameras, the RED company. In July last year, it introduced the world's first smartphone with a 5, 7-inch holographic screen - RED Hydrogen One. In addition to the usual 2D images, it reproduces 3D content without the help of special glasses, as well as content for virtual and augmented reality.
Holograms from the Future
By 2020, Japanese engineers promise to present the first models of holographic TVs based on technology developed by Daniel Smalley of MIT. And with the help of TeleHuman pseudo-holography technology, people will be able to talk with holographic images.
Microsoft has contributed with the development of holoport technology. It involves the transmission of a volumetric scanned image of the interlocutor online and the creation of its three-dimensional model.
Specialists of the Digital Nature Group laboratory from Japan have learned to create holograms using femtosecond lasers, which, moreover, can be touched by hands without fear of unwanted consequences. This became possible due to the reduction of the duration of laser pulses from nano- to femtoseconds.