"A holistic picture": an optical engineer - about holograms and their applications

- At the Russian ITMO University, you gave a course of lectures on holography and holograms.

Could you explain to people far from science what holograms are and how they can be used? 

- The photo does not contain any detailed information.

In fact, this is just a view through the keyhole.

We only have one angle of view, and the relative position of objects in the picture does not depend on our movements with our eyes or head.

And looking at a hologram is like looking out a window.

We can move, changing the point of view, and observe the picture from different angles.

In short, photography provides two-dimensional information, while a hologram provides more complete three-dimensional information.

The word "hologram" means "complete picture".

It was originally invented back in the 1940s as a way to access more information from X-ray images.

Inventor of holography Denesh Gabor received the Nobel Prize for this idea.

Today holograms are used not only for visualization, they have a wide range of applications.

Because they are difficult to counterfeit, for example, they are used to protect against fraud: on credit cards, banknotes and even drugs.

• Holographic marks on the 5,000 yen banknote

• Reuters

• © Issei Kato

- Tell us about promising holographic technologies?

“Today, full color holograms can be recorded on very thin and flat plastic layers — they are durable and weigh almost nothing.

One of the applications of such holograms is to use them as lenses.

Refractive lenses made of glass can be large and heavy.

But, using holograms, you can make flat, very large lenses, which are compact at the same time.

Two popular uses for these lenses are for concentrating (storing) sunlight to generate electricity and as a beamforming element in car headlights.

- Tell us about the holographic connection.

In science fiction films, characters often participate in negotiations in the form of holographic avatars ...

- The hologram of Princess Leia in Star Wars and the holographic deck in Star Trek certainly raised very high expectations!

Unfortunately, modern engineers are limited by the laws of physics - as we know them now.

Making light bend in free space is difficult.

However, engineers never give up, and many smart, hardworking professionals are trying to make such designs real right now.

Already today, they are producing virtual and mixed reality glasses, with the help of which you can see a person from different angles in real time, moving around a specially equipped studio.

3D glasses are already available, and there are even contact lenses with a similar effect.

• Holographic image of Elvis Presley at the Las Vegas show

• AFP

• © Ethan Miller / GETTY IMAGES NORTH AMERICA

- When will the first mobile devices for holographic calls appear?

“I’m afraid I’m not a fortuneteller, but I’m amazed at what has happened in the last 20 years.

It is difficult to explain to young people how unusual mobile phones are.

In my youth, the idea of ​​having a device that fits in your pocket and on which you can watch a movie and then call somewhere would sound crazy.

With regard to the creation of portable 3D communication devices, there are many prospects for their development.

Usually, holographic recording requires the use of laser radiation.

But there is also another way of capturing data, which is called integral mapping.

With multiple cameras, you take multiple shots at once under normal lighting conditions.

Then a three-dimensional image is created using clever computer algorithms.

Most mobile phones already have multiple cameras.

Considering the competition between technological solutions, I think that holographic bell devices are not a fantasy.

- Do you think holography opens up new opportunities for education?

- The same video lectures and distance learning have been available to people for several days.

If we add to them the available remote holographic communication, then this will undoubtedly open up new possibilities for the dissemination of information.

The better the way of communication, the fewer barriers to understanding and the greater the area for dissemination and access to new ideas.

I can clearly see the advantages of the online learning model in small specialized groups of 10-15 students, with whom training sessions and laboratory practice will be conducted.

As a teacher, I enjoy live communication with my students.

Perhaps the biggest catalyst for the widespread use of holographic technology will be the desire to achieve the greatest immersion or authentic experience, while avoiding the health hazards, waste of time and energy - everything associated with travel.

• Holographic portraits on display

• RIA News

• © Evgeny Biyatov

- What is holographic data storage?

- My phone can store about 100 GB of data, plus I have 1 TB on an external memory card.

The first hard drive I bought held 10MB, was ten times more expensive than my phone, and weighed like a large, hard metal bar.

However, he did not photograph.

High-capacity magnetic tapes hold about 10 TB and are used in filing cabinets that can hold up to ten thousand tapes.

All of these methods, including the use of semiconductor-based servers, involve storing data in 2D media, where information is read and output sequentially.

Holographic data storage is not the use of a plane, but the volume of the data carrier material.

Data warehouse capacity calculations usually assume that one cube wavelength is the basic storage unit of one bit.

Then more than 10 TB can be easily stored in 1 cm³.

In addition, all data can be written optically and read simultaneously at a very high transfer rate without wear or tear.

The challenges associated with the production of optical drives and storage media, especially rewritable data cubes, are enormous, but many academic and commercial research groups around the world are working on this type of technology, including the optics group at ITMO University.

- How else can you use holography?

- Recently I contributed to the compilation of a collection of short articles called "Roadmap to holography" for the Journal of Optics of the British Institute of Physics.

This collection describes the contribution to holography of the world's leading scientists, it also includes significant Russian research.

For example, at the Russian ITMO University, where I gave a course of lectures, the laboratory of digital and visual holography is actively working on the development of methods for ultrafast digital holography in the visible and terahertz frequency ranges.

Such methods are used in the development of new revolutionary-fast wireless communication channels that are much superior to the usual Wi-Fi, to study the formation of plasma channels caused by high-intensity laser radiation, and to measure the optical nonlinear properties of objects and materials.

Scientists are using holograms to scatter neutrons, explain how the human brain works, and even more efficiently produce renewable solar energy.

They are trying to optimize energy consumption in data centers, introducing digital holographic microscopy to detect diseases, including using mobile phones.

I can predict with some certainty - there is still a lot ahead of us.