Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: holograms – Page 19

Dielectric metasurfaces for next-generation holograms

Metasurfaces are optically thin metamaterials that can control the wavefront of light completely, although they are primarily used to control the phase of light. In a new report, Adam C. Overvig and colleagues in the departments of Applied Physics and Applied Mathematics at the Columbia University and the Center for Functional Nanomaterials at the Brookhaven National Laboratory in New York, U.S., presented a novel study approach, now published on Light: Science & Applications. The simple concept used meta-atoms with a varying degree of form birefringence and angles of rotation to create high-efficiency dielectric metasurfaces with ability to control optical amplitude (maximum extent of a vibration) and phase at one or two frequencies. The work opened applications in computer-generated holography to faithfully reproduce the phase and amplitude of a target holographic scene without using iterative algorithms that are typically required during phase-only holography.

The team demonstrated all-dielectric holograms with independent and complete control of the amplitude and phase. They used two simultaneous optical frequencies to generate two-dimensional (2-D) and 3D holograms in the study. The phase-amplitude metasurfaces allowed additional features that could not be attained with phase-only holography. The features included artifact-free 2-D holograms, the ability to encode separate phase and amplitude profiles at the object plane and encode intensity profiles at the metasurface and object planes separately. Using the method, the scientists also controlled the surface textures of 3D holographic objects.

Light waves possess four key properties including amplitude, phase, polarization and optical impedance. Materials scientists use metamaterials or “metasurfaces” to tune these properties at specific frequencies with subwavelength, spatial resolution. Researchers can also engineer individual structures or “meta-atoms” to facilitate a variety of optical functionalities. Device functionality is presently limited by the ability to control and integrate all four properties of light independently in the lab. Setbacks include challenges of developing individual meta-atoms with varying responses at a desired frequency with a single fabrication protocol. Research studies previously used metallic scatterers due to their strong light-matter interactions to eliminate inherent optical losses relative to metals while using lossless dielectric platforms for high-efficiency phase control—the single most important property for wavefront control.

3D integrated metasurfaces stacking up for impressive holography

Physicists and materials scientists have developed a compact optical device containing vertically stacked metasurfaces that can generate microscopic text and full-color holograms for encrypted data storage and color displays. Yueqiang Hu and a research team in Advanced Design and Manufacturing for Vehicle Body in the College of Mechanical and Vehicle Engineering in China implemented a 3D integrated metasurface device to facilitate miniaturization of the optical device. Using metasurfaces with ultrathin and compact characteristics, the research team designed optical elements by engineering the wavefront of light at the subwavelength scale. The metasurfaces possessed great potential to integrate multiple functions into the miniaturized optoelectronic systems. The work is now published on Light: Science & Applications.

Since existing research on multiplexing in the 2-D plane remains to fully incorporate capabilities of metasurfaces for multi-tasking, in the present work, the team demonstrated a 3D integrated metasurface device. For this, they stacked a hologram metasurface on a monolithic Fabry-Pérot (FP) cavity-based color filter microarray to achieve simultaneous cross-talk, polarization-independent and highly efficient full-color holography and microprint functions. The dual function of the device outlined a new scheme for data recording, security, encryption and information processing applications. The work on 3D integration can be extended to establish flat multi-tasking optical systems that include a variety of functional metasurface layers.

Metasurfaces open a new direction in optoelectronics, allowing researchers to design optical elements by shaping the wavefront of electromagnetic waves relative to size, shape and arrangement of structures at the subwavelength. Physicists have engineered a variety of metasurface-based devices including lenses, polarization converters, holograms and orbital angular momentum generators (OAM). They have demonstrated the performance of metasurface-based devices to even surpass conventional refractive elements to construct compact optical devices with multiple functions. Such devices are, however, withheld by shortcomings due to a reduced efficiency of plasmonic nanostructures, polarization requirements, large crosstalk and complexity of the readout for multiwavelength and broadband optical devices. Research teams can therefore stack 3D metasurface-based devices with different functions in the vertical direction to combine the advantages of each device.

Hard Light

When ordinary light, whether it comes from science fiction projectors or a magic spell, seems to have (or really does have) actual substance, it’s Hard Light. Hard light objects behave like any other object — chairs support weight, bullets kill, razors shave, and so forth. An illusory person made of Hard Light can pick up real things and interact physically with real people, even though they don’t technically exist.

Strictly speaking, hard light is not holography. A hologram is a sort of three-dimensional projection. It is not solid. If something is solid, it is, by definition, not a hologram.

That said, it’s easy to imagine holography being used in tandem with some other technology (Deflector Shields, perhaps) to produce a projection which seems solid to observers. The Holographic Terminal in its “real world” form comes to mind.

Circus in Germany Uses Holograms Instead of Animals to Stop Mistreatment

In the past, a trip to the circus was nothing without seeing some exotic animals doing impressive tricks. But as we become more aware of human impact on the world, and more inclined to be careful about how we interact with other species on earth, the simple pleasure no longer seems so pure. In fact, using other animals for our enjoyment seems deeply unethical, and, for many, precludes any circus-related enjoyment.

But one innovative circus has come up with a solution to this problem. Wanting to enchant visitors with traditional shows of the past without having to make shady ethical calls, they’ve gone for a different approach. Instead of performing these tricks with living beings, they’ve used technical advancements to achieve beautiful effects — and the internet is loving it.

Physicists Outline an Ambitious Plan to Simulate Black Holes With Holograms

Black holes are some of the most powerful and fascinating phenomena in our Universe, but due to their tendency to swallow up anything nearby, getting up close to them for some detailed analysis isn’t possible right now.

Instead, scientists have put forward a proposal for how we might be able to model these massive, complex objects in the lab — using holograms.

While experiments haven’t yet been carried out, the researchers have put forward a theoretical framework for a black hole hologram that would allow us to test some of the more mysterious and elusive properties of black holes — specifically what happens to the laws of physics beyond its event horizon.

Microsoft has a wild hologram that translates HoloLens keynotes into Japanese

What if neither distance nor language mattered? What if technology could help you be anywhere you need to be and speak any language? Using AI technology and holographic experiences this is possible, and it is revolutionary.

Microsoft has created a hologram that will transform someone into a digital speaker of another language. The software giant unveiled the technology during a keynote at the Microsoft Inspire partner conference this morning in Las Vegas. Microsoft recently scanned Julia White, a company executive for Azure, at a Mixed Reality capture studio to transform her into an exact hologram replica.

The digital version appeared onstage to translate the keynote into Japanese. Microsoft has used its Azure AI technologies and neural text-to-speech to make this possible. It works by taking recordings of White’s voice, in order to create a personalized voice signature, to make it sound like she’s speaking Japanese.

Microsoft has shown off holograms of people before, but the translation aspect is a step beyond what has been possible with HoloLens. This looks like it’s just a demonstration for now, and you’d need access to a Mixed Reality capture studio to even start to take advantage of this. Microsoft’s studios are equipped with lighting rigs and high-resolution cameras to capture a fully accurate digital hologram of someone, which isn’t something that can be done easily at home with a smartphone just yet.

New holographic technique opens the way for quantum computation

Photography measures how much light of different color hits the photographic film. However, light is also a wave, and is therefore characterized by the phase. Phase specifies the position of a point within the wave cycle and correlates to depth of information, meaning that recording the phase of light scattered by an object can retrieve its full 3D shape, which cannot be obtained with a simple photograph. This is the basis of optical holography, popularized by fancy holograms in sci-fi movies like Star Wars.

But the problem is that the spatial resolution of the photo/hologram is limited by the wavelength of light, around or just-below 1 μm (0.001 mm). That’s fine for macroscopic objects, but it starts to fail when entering the realm of nanotechnology.

Now researchers from Fabrizio Carbone’s lab at EPFL have developed a method to see how light behaves on tiniest scale, well beyond wavelength limitations. The researchers used the most unusual photographic media: freely propagating . Used in their ultrafast electron microscope, the method can encode in a holographic light pattern trapped in a nanostructure, and is based on an exotic aspect of electron and light interaction.

Is the universe a hologram?

Are you — is every person you’ve ever loved, every incredible sight you’ve ever witnessed — part of a hologram? Some scientists think so.

They argue that all the information in the universe may be stored on some sort of two-dimensional object. In this video, NASA astronomer Michelle Thaller delves into frontier science — an unchartered territory that may require a new level of physics to better understand.