Dive into the Future & Explore the Exciting World of Holograms

The word hologram may sound a bit futuristic, but its story starts at the end of the 16th century. The first recorded description of the Pepper’s Ghost effect was made by the Neapolitan scientist and scholar, Giambattista della Porta –  this illusion became especially popular in the middle of the nineteenth century, and used to entertain, and perhaps scare, spectators in theatres, museums and on other smaller stages for money. To be clear, those were not holograms, but were optical effects that made it possible to create realistic 3D images of objects and people.

The idea of 3D images has been around for a long time. Beginning life as a harmless joke, 3D imaging now finds applications in multiple fields, from Medicine to Telecommunication, Military purposes to Navigation, and so on. Afterall, it’s in 3D that human eyes see the world around us.

Holography is a relatively new technique that “enables a wavefront to be recorded and later reconstructed.” The definition suggests that we can use it to create and display realistic 3D images of any existing objects, which is a promising way to take advantage of holography in Science and Business.

Nowadays, reflection and transmission are the two main types of hologram. Still, many real-life implementations have a hybrid nature, and possess the attributes of both types. The mathematics of holograms is well known, and allows us to create detailed computer-generated holograms. Although the era of real holographic streaming is still simply a matter of time, it’s not that far away. Computer-generated holograms are approaching the real-time threshold and, combined with advanced compression algorithms and 3D holographic displays, can become all too real in the near future.

What are holograms, and where have you seen them?

You’ve probably seen a hologram this week (if not today). That’s right – holograms are all around us. Forget those science fiction fantasies of Princess Leia pleading for help from R2-D2, the ones you’re likely to have come across are nowhere near as glamorous. However, they are extremely useful.

The holograms you may have seen are even closer to you than you think –  in fact, they’re probably in your back pocket right now. Your credit card or driver’s license are perfect examples.

These holograms are created by splitting a laser beam into two separate beams, using an angled mirror. This then forms an object beam and a reflection beam, and heading in different directions, both are reflected off of other angled mirrors. The object beam is then reflected off of the object that will form the holographic image, and finally onto the end surface (also known as the holographic plate), while the reflection beam is directed straight onto the plate. As these two beams come together the 3D hologram is created.

You may have also seen holograms in the form of product authentications, available on the back of many product packets. Simple and effective, although as we have begun to unpack above, the technology behind them is rather complex.

Although we only dream of holographic television and holo-mobile phones, on the way to classic holograms, we can use other 3D imaging technologies that look spectacular and sometimes, can even replace holograms. 

The so-called holographic display market is large and sophisticated nowadays –  it’s expected to reach about $12 billion by 2030. And although invented centuries ago, some hologram-like imaging techniques are successfully used in modern shows and performances to this day.

What other types of holograms are there?

Alongside the examples above, there are various types of holographic solutions out there. Here we’ll take a look at some of the most famous, focusing only on those that don’t require any additional accessories, and can be seen by the naked eye.

The “Pepper’s Ghost” effect

Picture the scene. The year is 2012, the location, Coachella, one of the world’s most famous music festivals held in California. In the crowd, 80,000 fans are watching as rap icons Dr. Dre and Snoop Dogg take the stage.

Just as they end their set with “California Love,” originally performed by Dre and the legendary 2Pac, the stage goes black. Out of the darkness, a figure appears. There, standing right before the crowd is 2Pac himself. But how could this be? He died in 1996!

The rapper that arrived on the stage at Coachella was, in fact, a 3D projection, created with a hologram effect. It was made using an old holographic technique called the “Pepper’s Ghost” effect, and then updated to take center stage.

This is one way to recreate a ghostly holographic image, but, of course, it comes with its own challenges. Here are the pros and cons of this type of hologram:

Pros

• The “Pepper’s Ghost” effect can display large-scale projections, such as on-stage at Coachella, or be as small as a shoebox, making it one of the most versatile holographic projection techniques available.
• It creates a truly extraordinary effect, that when combined with the celebrity factor, has every capability of making international headlines.
• This is a well-established technique that has been tried and tested over many years.

Cons

• To create this illusion, you need a sufficient amount of plexiglass (placed at a 45º angle on the stage where you would like to display the holographic image), making the installation difficult and heavy.
• It is dependent on light factors, meaning it’s vital to ensure that the overall arena is dark enough to make the projection visible.
• Once you try to introduce other elements, such as Snoop Dogg in this case, the challenges only increase. The positioning and movements of the real-life elements need to be carefully planned and coordinated, so that the performer doesn’t come into contact with the glass or obscure the image in some way.

The Holographic Smokescreen

Similar to the “Pepper’s Ghost” effect, the holographic smokescreens work by using artificially generated smoke, or a semi-transparent net as a “screen” for the hologram to be projected onto. Although, in this case, the projection comes from behind rather than below it, creating that spectral image effect (a ghost-like projection) which gives the impression of a hologram.

The holographic smokescreen and net are widely used in the theatre when a specific scene calls for a spectral image, unlike the 2Pac projection; usually this type of holographic projection is designed to appear slightly translucent. Let’s take a quick look at the pros and cons of the holographic net technique:

Pros

• An effective technique for stage productions, as it creates a ghostly atmosphere and effect.
• Well-used and established as a theatre technique.

Cons

• Does not integrate well in the real world, as additional characters would be either left behind or in front of the semi-transparent net.
• When smoke is used, other characters interrupt the effect, making the effect temperamental in terms of surrounding environmental factors, like lights.

Holographic Nets

One of the latest technologies to enter the holographic world are holographic nets, an almost transparent curtain of LED lights which display images in a variety of colours. These LEDs are programmed to create images that present a 3D holographic effect.

Holographic nets have been used for everything, from small displays to covering entire buildings with colourful visuals. They provide optimal advertising opportunities for companies looking to display their brand in lights.

Pros

• Ability to create large-scale displays up to the size of a building.
• Provides flexibility in its application, can be used flat or curved.

Cons

• Although the final result is effective, it is just an imitation of a 3D image.
• Not as immersive as other variants, as the viewer is always aware they are looking at a screen.

Holographic Spinning Mirror Technique

A simple, yet effective solution. The impression of a 3D image is made by placing a spinning mirror at an angle and projecting a high-speed video onto it, which is then reflected to form the display.

Developed in the University of Southern California (USC), the solution was designed as a new innovation in 3D holographic technology.

Pros

• Creates an effective optical illusion of a 3D hologram.
• Efficient in displaying a 3D version of a video to a specific scale.

Cons

• Introduced in 2007, this technology has seen very little development since then.
• It is limited in size to the device, which restricts its usage.

Semi-transparent OLED screens

In recent years, serious investment has been made into transparent OLED screens by some of the biggest names in electronics manufacturing. These new inventions feature a screen filled with organic light-emitting diodes, which react to an electric current to form an image.

In terms of 3D effects, the result is a 2D image which appears to be 3D, creating the illusion of a hologram on the screen. However, it is possible that this could be the future of our living room TV experience, and a new advancement in the advertising world.

Pros

• Very new to the market, the technology is still rapidly developing and new versions are imminent.
• Creates a contemporary way of displaying content and gives a little more flexibility.
• Provides a bright platform for displaying content.

Cons

• Images displayed are 2D illusions of 3D images.
• With a transparency level of +40% (meaning the image isn’t entirely see-through) some background will still be visible.

Holographic Pyramids

These popular holographic solutions come in two types: the DIY holographic pyramid that you can place on top of your smartphone or tablet at home, or the infinitely more professional constructed holographic cubes, also containing a pyramid alongside a screen, that are sold online by many retailers.

These hologram pyramids utilise reflections in a similar way to the “Pepper’s Ghost” effect, creating the appearance of a 3D hologram floating within a case. This type of imagery works due to the 45º positioning of the sides on the pyramid on the glass, giving the impression of a hologram reflected within.

While the technology is impressive, there are both pros and cons for users:

Pros

• Creates a holographic illusion that makes the image on your screen appear as if it is a 3D hologram.
• This type of installation can be made professionally, or recreated for home entertainment purposes using homemade constructions.

Cons

• Only works on a small-scale and is limited to the size of the enclosure, pyramid, and screen involved – current maximum size is around the size of a table.
• Results vary. Professional pyramids produce much more realistic results than DIY versions, which look more like a reflection rather than a 3D image. Such technology must remain inside the cube or pyramid, making it difficult to scale or transport, and limiting its usage.

Laboratory-only creations

Like we said at the start, the world of ‘Star Wars’ isn’t here quite yet, but the technology is real. And this is where that million dollar question -“How do holograms work?” – comes in.

The latest solution, created in Brigham Young University (US), is very different to the previous holographic projector operation of the “Pepper’s Ghost” effect, involving more equipment and stricter laboratory conditions.

In 2018, the team at BYU released the news that they had created a true 3D hologram, or as they prefer to call it, a “volumetric image.” The solution uses a laser to trap tiny particles and control their movements to create an image. This is precisely why this technique is called, “lab-only”, as it can be dangerous to create and could result in serious burn injuries.

Additional colored lasers illuminate the particle path, making it visible. Think of this like that old photography trick which uses long exposure to “write” with torches at night, but instead of flashlights and cameras you have lasers, and, well, more lasers.

Pros

• This is as close to a true 3D hologram as society has got – a complete 3D volumetric image.
• The technology is ground-breaking and may pave the way for future advancements.

Cons

• This is only for lab technology, due to the use of lasers. There is no “how to build a hologram” at home variant here.
• While the results are pretty spectacular, at the moment the technology can only create small, simple images, so we need to keep that dream of Blade Runner style holograms for another day.

Holoboxes

The idea behind the PORTL holoboxes is to bring people’s holograms to any location around the globe. Although the holobox is no more than a display, according to many reviews, it successfully creates the effect of presence as if a person sits right there, behind the glass. 

The technology is available in the form of larger-size boxes and tabletop units, with varied prices. Big installations cost from $65,000 to $200,000, and smaller units cost around $5,000. The above obstacles form the pros and cons of this product.

Pros

• The technology creates a ‘real-life’ experience;
• It allows contactless communications, which is advantageous in pandemic and post-pandemic times;
• It gives people a chance for effective distant communications, which is a great way to reduce transport expenses.

Cons

• The price of the product is high, which is unsuitable for the mass market;
• The technology is 2D and is not visible from all angles;
• It requires specific equipment for recording and displaying holograms.

Tactile holograms

As we all know, a hologram is a 3D image at the highest quality a human eye can perceive. But why should we limit ourselves to only visual information? We can create even deeper illusions, and involve haptics.

In 2019, researchers from the School of Engineering and Informatics of the University of Sussex presented new technology that makes it possible to touch 3D images. In fact, they are not just images. The technology uses an LED projector, a speaker array, and a foam bead, and the ultrasound emitted by the speakers suspends the bead in the air and moves it so quickly that the light beam of the projector reflected from the bead makes a human eye perceive its movement as a whole static picture in mid-air.

Not only can they see, but people can also interact with this type of hologram, touch them and feel their shape and size. It becomes possible thanks to ultrasound waves being able to produce mechanical impact. If we look a bit further, we may surprisingly witness that the tactile hologram technology is the first step towards the concept of the ultimate display by Ivan E. Sutherland.

Pros

• Super-realistic effect;
• Next step towards the ultimate display;

Cons

• The complexity of implementation;
• The embryonic stage of the technology.

Contactless Holograms

Opposite tactile holograms with super-realistic images, lies the idea of contactless holograms that make it possible to interact with physical things without actually touching them. Such communication and interaction patterns can be advantageous in poisoned or dangerous environments, so that people can avoid the physical touch, and deal instead with high-quality 3D images. In particular, the COVID-19 pandemic is an example of a threatening environment, where this holographic device would be advantageous.

Pros

• This interactive technology is advantageous in particular cases.

Cons

• Not holograms.

3D holograms + 5G networks

Holograms are a technology which requires complex computations that consume sufficient processing and data transferring resources. Any tremendous benefits that holograms bring to life are almost useless without the opportunity to send and receive corresponding data flawlessly.

It’s no surprise that 3D images are developing closely alongside such data transmission technologies like the 5G network. Together they create amazing fiction-like examples of augmented reality.

Conclusion

Although the general goal of creating and implementing actual holograms is yet to be achieved, the state of 3D and hologram-like image technologies allows us to choose from many options depending on the goals we’re aiming for. Either in Medicine or Science, Retail or Entertainment, the era of 2D is over, and 3D technologies are officially in the mainstream.