"Metaholograms," which can cast multiple high-fidelity images without any crosstalk, is a huge step forward in holography.
(Photo: Unsplash/ Theo Eilertsen Photography )
Thanks to this significant advancement, technology like virtual/augmented reality (AR/VR) displays, data storage, and picture encryption can now take new directions.
Revolutionary Metaholograms and What They Can Do
Metaholograms are better than regular holograms because they have a wider operating bandwidth, better image clarity, wider viewing angles, and smaller sizes. One big problem is that they can only hold so much information and can only show a few separate images at a time.
With current methods, providing multiple display channels without inter-channel crosstalk when images are projected can be difficult. The new study, released in the journal eLight, finds a creative way around this problem using the k-space translation design strategy.
This method allows several target images to be easily moved from the "displayed" to the "hidden" states. The proposed metahologram comprises millions of microscopic polysilicon nanopillars, each around 100 nm across, whose spin angles vary with their spatial position and use a geometric phase encoding technique.
A flat glass waveguide that moves light that comes in is an integral part of this technology. With help from factors like polarization and angle, the device can change how up to six separate high-quality pictures are projected without any crosstalk.
The researchers also combined different methods to make a two-channel full-color metahologram and an eighteen-channel metahologram. This new idea can improve AR/VR displays by allowing more realistic and complex scenes to be projected. It also claims improvements in image encryption, where data can be hidden in many holographic channels to make it safer.
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Taking Metaholograms to New Places
A related study by Pohang University of Science and Technology researchers published in June 2023 showed incredibly advanced metamaterials. Their creation was a metahologram with visible and ultraviolet spectra.
Some of the issues with metasurfaces, such as their limited capacity for information storage and their limited ability to produce visible spectrum holograms, are circumvented. The study team made the holographic transmission far more successful by adding a thin layer of specifically created gas compositions to the metasurfaces.
Recording two distinct holographic phase profiles onto a single metasurface could double the amount of information stored. Liquid crystal, a typical part of LCD panels and phones, allows light spin to be changed in any direction, making the idea a reality.
The group created a device that displays various holograms according to the presence or absence of an electric field. The study's leading author, Professor Junsuk Rho, highlighted its significance by pointing out that it circumvented the issues associated with metaholograms operating solely in the visible spectrum.
According to him, the suggested metasurface might be helpful in security technologies like identification, passports, and measures to prevent counterfeiting. This work's findings make creating high-performance metaholograms much easier.
The advancements in these areas greatly enhance the production of high-performance, much larger data-storing metaholograms. Enhanced data encryption and storage capabilities are only a few of the many prospective applications for which it has excellent potential.
The big step forward in holography, metaholograms, will significantly impact many scientific areas. Since researchers are always looking for new opportunities, it is reasonable to expect many significant findings shortly.
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