Tag Archives: hologram

Scientists design holograms you can see, hear and feel

Holograms have long been a staple of science fiction movies such as Star Trek or Star Wars — but they’re no longer the works of fiction. Researchers in Britain have engineered a display prototype that simultaneously produces visual, auditory and tactile content. This means that 3D representations — such as a butterfly, a globe, or an emoji — can be seen, heard, and touched without the need for an external device like a virtual reality headset.

A globe created by the Multimodal Acoustic Trap Display. Credit: Eimontas Jankauskis

This isn’t the first holographic display. However, unlike previous renditions that are rather slow and short-lived, this version can produce tactile and auditory content, not just a 3-D image.

In order to allow users to interact with the hologram with their hands, the prototype employed acoustic tweezers that can move and manipulate tiny objects. In this case, particles that can be illuminated in red, green and blue (RGB) light to control the color of the 3-D images just like on any regular display. Previously, acoustic tweezers were employed to successfully to levitate objects.

Essentially, the Multimodal Acoustic Trap Display (MATD) made by researchers at the University of Sussex uses a small array of tiny speakers to both trap particles and generate sounds, as well as generate tactile feedback. All of this — seeing, hearing, and touching — makes the hologram genuinely seem like a real object.

In one demonstration, the researchers generated a holographic countdown timer that the user can start and stop by simply tapping their fingers.

“Even if not audible to us, ultrasound is still a mechanical wave and it carries energy through the air. Our system directs and focuses this energy, which can then stimulate your skin to feel content,” Ryuji Hirayama, lead author of the new study, told AFP.

“The feeling of the tactile sensation is like a gently spraying your hand with pressurized air.”

Besides the obvious uses for entertainment, the researchers say that their prototype could find other useful uses from computing to biomedicine, allowing researchers to visualize complex systems in unprecedented detail.

The findings appeared in the journal Nature.

Credit: RMIT University.

Nano-holograms 1,000 times thinner than the human hair pave way for smartphone-generated holograms

Credit: RMIT University.

Credit: RMIT University.

For decades, holograms have been a staple of science fiction. You’ve seen them in Star Wars or Avatar, but soon enough you might enjoy them virtually everywhere. That’s because a team of researchers from Australia and China was able to design a nano-hologram that’s thin enough to work with modern electronics. No 3D-goggles are required to see these holographic images which can be 1,000 thinner than the human hair.

Conventional holograms give the impression of a 3D object by modulating the phase of light. This gives the illusion of 3-D depth but to generate enough phase shifts, each hologram needs to be at least as thick as the phase-shifted optical wavelengths. Australian researchers from RMIT University, along with Chinese colleagues from the Beijing Institute of Technology (BIT) managed to pull a workaround by using a topological insulator. This is an exotic class of materials that has the unique ability to conduct electricity at the surface, but not on the inside through the bulk material.

Topological insulators also have unique quantum properties like a low refractive index at the surface and a ultra-high refractive index in the bulk. When a very fast direct laser is shone a thin film made from such exotic materials, it’s possible to enhance phase shifts for holographic imaging.

“We discover that nanometric topological insulator thin films act as an intrinsic optical resonant cavity due to the unequal refractive indices in their metallic surfaces and bulk. The resonant cavity leads to enhancement of phase shifts and thus the holographic imaging,” the researchers wrote in the journal Nature Communications.

For instance, the holograms demonstrated by the researchers operated at 60 nanometers of 3 mm × 3 mm in size

T-rex in your pocket

hologram dinosaur

(a) Original image of the dinosaur object. Note: this figure is not included under the article CC BY licence; Indominus Rex image is reproduced with permission from the publisher Comingsoon.net and copyright owner Universal Studios. (b,c) SEM images of the laser printed hologram patterns. The scale bar is 50 μm for b and 10 μm for c, respectively. (d–f) Holographic images captured by illuminating the nanometric holograms using 445, 532 and 632 nm continuous wavelaser beams. Scale bars for d–f are 1 mm. Credit: Nature Communications.

“Conventional computer-generated holograms are too big for electronic devices but our ultrathin hologram overcomes those size barriers,” said  RMIT University’s Distinguished Professor Min Gu in a statement.

“Integrating holography into everyday electronics would make screen size irrelevant — a pop-up 3D hologram can display a wealth of data that doesn’t neatly fit on a phone or watch.

“From medical diagnostics to education, data storage, defence and cyber security, 3D holography has the potential to transform a range of industries and this research brings that revolution one critical step closer.”

The next step for the team is developing a rigid thin film that can be placed on an LCD screen, such as that on a smartphone or notebook, to enable everyday use of 3D holographic display. This will be immensely challenging as it involves shrinking the nano- hologram’s pixel size even further — at least 10 times smaller than it currently is.

“But beyond that, we are looking to create flexible and elastic thin films that could be used on a whole range of surfaces, opening up the horizons of holographic applications.”

Scientific reference: Zengji Yue, Gaolei Xue, Juan Liu, Yongtian Wang, Min Gu. Nanometric holograms based on a topological insulator material. Nature Communications, 2017; 8: 15354 DOI: 10.1038/NCOMMS15354

Demonstration of the nanomaterial holographic generator which is supposed to advance various holographic applications, according to the researchers. Credit: ACS Nano

Full-color 3-D holograms made with atomic-sized nanomaterials

Using nanomaterials whose tiny surface was etched with various geometrical patterns, researchers at Missouri University of Science and Technology demonstrated the first full-color 3-D holograms with such an approach. Their work could lead to anything from colorful 3D holograms projected from the smartphones of the future or better, more secure credit card holograms.

Demonstration of the nanomaterial holographic generator which is supposed to advance various holographic applications, according to the researchers. Credit: ACS Nano

Demonstration of the nanomaterial holographic generator which is supposed to advance various holographic applications, according to the researchers. Credit: ACS Nano

The new method used involves ultrathin nanometer-scale metallic films with metasurfaces that can be used to manipulate light’s wavefront. The metasurface hologram developed by the team consists of an aluminum film 35 nanometers thick, perforated with tiny rectangular holes 80 nanometers high by 160 nanometers wide. A microfabrication process known as focused ion beam milling was used to create different orientation angles.

To make holograms you have to manipulate the light’s wavefront. Dr. Xiaodong Yang and Dr. Jie Gao, both assistant professors at Missouri S&T, used ultrathin metal films with variable metasurfaces. Just so you can get an idea of the scale involved, the team metal films were only 35 nanometers thick whereas the typical human hair is 100,000 nanometers wide. That’s only 10 times thicker than the diameter of DNA.

Using ion beam milling, the researchers then made tiny rectangular holes of 160 by 80 nanometers into the metasurface with various orientation angles. It was then only a matter of firing three different lasers (red, green blue) onto the metasurface to create  “clean and vivid full-color holographic images with high resolution and low noise.”

By varying the intensity of each laser, the researchers produced the primary colors — red, green and blue — as well as the secondary colors known as cyan, magenta, yellow and white. Mixing these colors offers virtually the whole spectrum.

To demonstrate their work, the letters C, M, Y and W, a Rubik’ cube and an apple were projected as 3-D holograms.

“By adjusting the orientation angle of the nanoscale slits, we are able to fully tune the phase delay through the slit for realizing the phase modulation within the entire visible color range,” says Yang. “In addition, the amplitude modulation is achieved by simply including or not including the slit. Our holograms contain both amplitude and phase modulations at nanometer scale so that high resolution and low noise holographic images can be reconstructed.”

Previous methods produced 3-D holograms in a limited color spectrum, but the new work can reconstruct almost all visible colors.

Findings appeared in ACS Nano

Scientists develop a ridiculously cheap acoustic tractor beam

Researchers working on acoustic holograms have created a new sonic tractor beam system for less than it costs to get lunch.

Image via Youtube / Nature Videos.

Image via Youtube / Nature Videos.

A little bit — and I mean that literally — of Star Trek has just passed into the real world. Scientists have developed a sonic system which can push or pull on objects just like the show’s famous tractor beams, only much smaller. While the idea of using sound to manipulate objects from afar isn’t new, no one has ever done so using a system as simple and cheap as this. The full device costs a little under 10$ to manufacture.

The device, created by engineers at the Max Planck Institute for Intelligent Systems in Germany, consists of just three parts — a 3D-printed plastic disk, a thin plate of brass, and a small speaker which you could probably find in any watch alarm.

“We were genuinely surprised that nobody had ever thought of this before,” team-member Kai Melde told Popular Mechanics.

Acoustic tractor beams work by transferring force to a far-away object through the vibrations of a medium, or what our ears perceive as sound. Last year, University of Bristol engineers developed the first one-sided acoustic tractor beam by slapping 64 small speakers together and tuning them to move bits of polystyrene around. It worked, and was quite awesome to watch, but it was incredibly inefficient and expensive to scale up — each speaker required constant tweaks in the sound-waves it produced to keep the acoustic hologram stable.

So, the Max Planck team decided to try and simplify the device. Instead of using banks of speakers and tuning each one to create the acoustic hologram, they used a single speaker on which they fixed a patterned, 3D-printed plastic filter.

“It worked even better than we hoped,” Melde added.

The hologram they produced was so complex, that they estimate 20,000 unfiltered speakers working together would be needed to achieve something similar.

But there are also limits to the device. It only sends the hologram in one direction and it can’t be angled, meaning that it can move objects around on the pattern it’s designed for but can’t for example push them out of it once they’re in the air. A new plastic disk has to be printed for any new pattern required. And in its current form, the beam only works in two dimensions (moving an object around on a flat plane), so it can’t actually push or pull anything yet.

The team hopes that with further development, these issues can be overcome. There’s a lot of excitement for acoustic tractor beams, as they could revolutionize the way we think of transport, medicine, and a wide range of other fields.

“There’s a great deal of interest in using our invention to easily generate ultrasound fields with complex shapes for localised medical diagnostics and treatments,” lead researcher Peer Fischer told New Atlas. “I am sure that there are a lot of [other] areas that could be considered.”

But for now, the fact that we can create a working tractor beam for less than a good pair of jeans will cost you is simply amazing.

The full paper, “Holograms for acoustics” has been published in the journal Nature.

femtosecond laser hologram

What touching Fairy Holograms in mid-air looks like

femtosecond laser hologram

Most people would love to have a holographic display in their room, and seriously you might not have to wait too long for this to happen. For instance, the HoloLens is definitely impressive and will be out soon be commercially available to the public. Granted, it’s not quite holographic technology – more like virtual reality. What about holograms which you can touch?

Femtosecond laser

That definitely sounds innovative, and honestly I couldn’t expect anything less considering this was achieved by the Digital Nature Group, a lab which previously demonstrated 3D mid-air acoustic manipulation or graphics generated by levitating objects. Using a femtosecond laser which shoots ultrashort laser pulses, with durations approaching the timescales of fundamental atomic and molecular processes, the Japanese researchers excited matter to emit light at an arbitrary 3D position.

The  “Fairy Lights” system fires every millionth of a billionth of a second, and these pulses are responsive to human touch. Effectively, by swiping your hand, for instance, across a hologram’s pixels you can manipulate and control it.

“You can’t actually feel the videos or pictures, and although you can project a video, you can’t interact with it by touching it. So, if we can project an image in a three dimensional form, and if you can touch it, then you can make something where you’ll think that there actually is something there,”  said Dr. Yoichi Ochiai from Tsukuba University of the touchable hologram.

holograms spatial

“There are two methods of rendering graphics with a femtosecond laser in air: Producing holograms using spatial light modulation technology, and scanning of a laser beam by a galvano mirror. The holograms and workspace of the system proposed here occupy a volume of up to 1 cm^3; however, this size is scalable depending on the optical devices and their setup,” the researchers write.

The future is now: Microsoft rolls out mind blowing holographic computing

Microsoft demonstrated just how far they’ve come with their augmented reality HoloLens project – and it’s far. Virtual browsers on your wall, virtual dogs, the weather in your cup, holograms following you to the kitchen… all that and many more were showcased by Microsoft at the Build Conference.

I’ll be honest with you, I didn’t know we have this technology. It’s all a matter of slimming this tech down and making it more fashionable, and it’s basically good to go! Of course, Microsoft didn’t work alone on this project – for every moving hologram or dynamic app there’s some work done by someone from NASA, Autodesk, Sketchfab, and more. But these are the organizations that will also gain something from this technology – after all, having holograms and all that is cool, but it can be extremely useful as well, and it will be up to them to find and design new uses for it. I’m not sure exactly what NASA has in mind, but I can imagine that operating things on holograms on the ISS would save a lot of trouble.

But perhaps the field which will benefit the most is medicine.

“The mixed reality of the HoloLens has the potential to revolutionize [medical] education by bringing 3D content into the real world,” said CWRU’s Mark Griswold from the BUILD stage, before demonstrating how, “using holograms we can easily separate and focus in on individual systems.” The result is like having access to every facet of the famed Bodies exhibition at once, directly in front of you, any one aspect of which you can examine more closely before retreating back to surface level.

Just imagine – animating blood flow through veins, zooming in and out as you desire… the applications are endless. If medicine’s not your thing, think about the engineering, design, 3D printing, plane flight… I know I’m repeating myself, but the applications are endless. I’m just bamboozled that this technology is available today.

How much would something like this cost? How would you even design apps for it? I have no idea. I guess we’ll just have to wait and see.

Our Universe may be just a Hologram, complex simulations show

In a black hole, Albert Einstein’s theory of gravity clashes with quantum physics; for decades, scientists have tried to find a way to bridge the cap between these monumental theories, but so far, they simply seem irreconcilable. But the conflict could be solved if our Universe were in fact a holographic projection.

String theory, dimensions and holograms

The Calabi–Yau manifold, a special type of manifold that is used in String Theory. Via Wikipedia.

Before we start getting into the research, there’s a few things I want to explain, because the field is complicated and often hard to understand.

First of all, don’t think of a hologram that’s Matrix or Star Trek style. A holograph is a mathematical representation of something inside something else. It’s like a video playing on your screen: it’s there, but it doesn’t actually take place on your screen. Furthermore, on your 2D screen, you can watch 3D and even 4D representations (time being the 4th).

String Theory is an very popular theory among modern physicists. The essential, simplified idea behind string theory is this: all of the different ‘fundamental’ particles in all the Universe are made up of one basic object: a string. String Theory is also an incredibly ambitious idea – it aims to provide a complete, unified, and consistent description of the fundamental structure of our universe – something which is considered to be the Holy Graal of physics.

But String Theory is not proven yet, and researchers have huge problems making the math behind it work. Basically, to explain some of the things that are going on, they need 10 dimensions to make the math work. But to explain other things, they need a 1 dimensional Universe. This idea of a holographic Universe is the best one so far that makes both ideas work. Here’s how.

A holographic Universe

Artistic Representation of a Black Hole. Via Nature.

In 1997, theoretical physicist Juan Maldacena proposed an audacious model of the Universe – one in which gravity arises from infinitesimally thin, 1 dimensional vibrating strings; right from the start, this model challenged, thrilled, and scandalized researchers, but there was even more to it: it proposed a 10 dimensional Universe (9 + time), and explained that it was simply a hologram – that all the real action would play out in a simpler, flatter cosmos where there is no gravity. Hard to fathom, right?

But the idea caught pretty well in the world of physicists, because as hard to believe as it seems, it has two major advantages:
– it takes the popular yet unproven string theory one step further to completion
– it bridges the gap between Einstein’s relativity and quantum mechanics.

If, through an analogy, we consider the two theories to be two different languages, with some common things but many differences, Maldacena’s theory would be a Rosetta stone – allowing physicists to translate back and forth between the two languages, and solve problems in one model that seemed intractable in the other and vice versa. But the validity of his claims was still a huge question mark; basically, his claims were a little more than educated, plausible, fitting guesses.

Now, in two different papers, Yoshifumi Hyakutake of Ibaraki University in Japan and his colleagues provide the first pieces of evidence that Maldacena’s ideas are more than wishful thinking.

“They have numerically confirmed, perhaps for the first time, something we were fairly sure had to be true, but was still a conjecture — namely that the thermodynamics of certain black holes can be reproduced from a lower-dimensional universe,” says Leonard Susskind, a theoretical physicist at Stanford University in California who was among the first theoreticians to explore the idea of holographic universes.

In the first paper, Hyakutake computed the properties of a black hole (internal energy, position of the event horizon, entropy and others) based on String Theory, as well as the effects of so-called virtual particles that continuously pop into and out of existence. In the second one, he calculated the internal energy of the corresponding lower-dimensional cosmos with no gravity. The two results matched.

“It seems to be a correct computation,” says Maldacena, who is now at the Institute for Advanced Study in Princeton, New Jersey and who did not contribute to the team’s work.

But even he noted that neither of the model universes explored by the Japanese team resembles our own.

The first one (with ten dimensions) has eight of them forming an eight-dimensional sphere. The lower-dimensional, gravity-free one has but a single dimension, and “its menagerie of quantum particles resembles a group of idealized springs, or harmonic oscillators, attached to one another”, as Nature explains. Still, Maldacena believes this is extremely promising work, and he hopes that one day, all the forces in our Universe can be explained simply through quantum mechanics and string theory.

A 3D view of the malaria sperm

Aside from being really cool and enabling wicked video game graphics, 3D imaging is also extremely useful in research, entering the labs as one of the most powerful tools in the 21st century.

Courtesy of the Rowland Institute at Harvard

Courtesy of the Rowland Institute at Harvard

Using an imaging technique known as high-speed holographic microscopy, Laurence Wilson, a fellow at Harvard’s Rowland Institute, created detailed 3D images of malaria sperm – the cells that reproduce inside infected mosquitoes. This could provide very valuable information in fighting the disease.

“The working assumption was that this structure moved through a consistent clockwise beating,” Wilson said. “But what we found was, if you look at the malaria swimming, it doesn’t just move in a ‘right-handed’ way — it actually turns out to be a very general motor. “The only way we could identify this was because we could see the 3-D structure,” he continued. “We could never do that before, and we found that there’s a whole zoo of shapes and waveforms it uses. What stuck out, however, was the idea that it does a right-handed stroke, then a left-handed stroke — so it relies on the strict alternation between the two.”

The main thing this 3D representation does is provide more information about how these cells move, and indirectly, how other similarly built cells travel (like cilia in the lungs, for example). The main thing, however, is to develop new strategies to combat malaria. For many researchers like Wilson, the structure of Malaria is an extremely interesting and useful to understand topic.

“That’s how you get a sperm tail beating, or cilia beating in your lungs,” Wilson said. “The nice thing about malaria, however, is that from a mechanical point of view, it’s relatively primitive. Unlike other model systems we looked at — all of which have a head or cell body attached — malaria has no accessory mechanical structures. There’s only a cell membrane and some DNA arranged along its length.”

Holographic microscopy is not exactly a novel technology. It basically creates numerous 2D images and them stacks them above each other to develop a three dimensional model. Because the data is acquired so rapidly, the image is sampled thousands of times per second, thus enabling imaging of things like this malaria sperm.

“Holographic microscopy has been used for some time, but no one has tried to do exactly this sort of imaging before,” Wilson said. “No one has ever used it to look at the shape of something in this way, or in the same level of detail that we have.”

While the study provides a very clear picture yet of how such cellular motors work, Wilson and his team are already working on ways to build on this work, figuring out what can goes wrong in the human body and how.

“The hope is if we know how this malaria sperm works, then when similar cellular motors go wrong, we can say why they’ve gone wrong,” Wilson said. “When these things go wrong in the human body, it can lead to problems like infertility and polycystic kidney disease — all sorts of unfortunate things can happen if these structures don’t work properly.”

More info and a video on MIT News.

Two images of a live human subject as seen through flames. When viewed in infrared or white light, the man is almost completely occluded (left). The new system reproduces the image behind the flames using holography, revealing a man wearing a t-shirt and glasses (right). Credit: Optics Express.

Infrared holographic imaging allows firefighters to see through flames

Two images of a live human subject as seen through flames. When viewed in infrared or white light, the man is almost completely occluded (left). The new system reproduces the image behind the flames using holography, revealing a man wearing a t-shirt and glasses (right). Credit: Optics Express.

Two images of a live human subject as seen through flames. When viewed in infrared or white light, the man is almost completely occluded (left). The new system reproduces the image behind the flames using holography, revealing a man wearing a t-shirt and glasses (right). Credit: Optics Express.

I have nothing but the deepest admiration and respect for fighters – always faithful in the face of peril and always ready to put their necks on the line in order to save people from the hellish depths. As one can imagine, firefighting tech has evolved a great deal from simple fireproof clothing and a bare axe, still there is still much that can be done. One of the great challenges firefighters face is seeing through thick smoke and flames in order to reach people in need, and a recent breakthrough by a group of Italian scientists that devised an infrared digital holographic imaging system might change all that forever.

Currently, some firefighting departments employ infrared cameras and imaging systems in order to see through smoke. However, the system becomes useless if flames are in the vicinity, as the intense radiation obstructs  the sensitive detectors and limit their use in the field.

“IR cameras cannot ‘see’ objects or humans behind flames because of the need for a zoom lens that concentrates the rays on the sensor to form the image,” says Pietro Ferraro of the Consiglio Nazionale delle Ricerche (CNR) Istituto Nazionale di Ottica in Italy. By eliminating the need for the zoom lens, the new technique avoids this drawback.

To tackle this issue, the Italian researchers devised an infrared camera and detector that builds a holographic image – a 3-D image of an object. To create a hologram, like the one you have on your credit card, a laser beam is split into two  – an object beam and a reference beam. The object beam is shone onto the object being imaged, and it is combined with the reference beam, the interference pattern produces a 3-D image.

The difference between life and death

The holographic imaging system developed in Italy employs a beam of infrared light which is widely dispersed throughout a room. Unlike visible light, infrared isn’t blocked by smoke, but it does bounce off objects or people. The bounced off IR is then collected by a holographic imager. The information is then decoded by a computer to reveal the objects or people behind smoke or flames – all in a live 3-d scene.

In the video below you can see just how well the system works in this comparative study – on the left, imaging with simple infrared, on the right holographic imaging.

The next step researchers plan on making is to scale the system so that it may fit in firefighting gear. Also, the system could be installed as a fixed installation in buildings, tunnels and such, so that firefighters, even without the gear on hand, can be directed to the right spot. Other applications, like medical, are also viable options.

“Besides life-saving applications in fire and rescue, the potential to record dynamic scenes of a human body could have a variety of other biomedical uses including studying or monitoring breathing, cardiac beat detection and analysis, or measurement of body deformation due to various stresses during exercise,” Ferraro says. “We are excited to further develop this technology and realize its application for saving and improving human life.”

Findings were reported in a paper published in the journal Optics Express.

Holographs – coming soon to a screen near you

The race to develop holographic videos will have its winners and its losers, but it’s obvious by now that this isn’t some distant sci-fi technology, but rather a work in progress, as rival research teams battle to be the first to control lasers in a way that would allow displaying 3D videos.

The evergrowing power of computers allows continuous progress in numerous fields, including this one, and as computers become more and more performant, scientists start to think about an inexpensive and portable system that can handle holographic displays, according to Michael Bove, a holographer at the Spatial Imaging Center at the Massachusetts Institute of Technology’s Media Lab.

“We now see a clear path to that [system],” he said. With several research groups actively pursuing the problem from different angles, he said, we may see holographic video in homes within ten years.

In order to create a holograph, lasers are used to write on a transparent surface, changing the material’s properties and mimicking light scattering of a real object. After one image is displayed the laser pulses again and reorients the material’s molecules so that it displays another image. The fuss around this technology is so large that it caused a significant amount of friction between the two teams, which sadly, will probably lead to slowing down the developments.

More details HERE.